I have a tall skinny baby and we switched to a convertible carseat for her. Since your baby is too young to ride forward a convertible would be your best bet because it will turn around when he is ready to face forward. It might also be able to fit him until he is ready for a booster. We use a Britax Boulevard which is more than your budget but the Evenflo Symphony has gotten great reviews and is very affordable. Chicco makes an umbrella style stroller called the Trevi. We have a Chicco Cortina and we love it. You could probably swing both the Symphony and the Trevi for under $300. Good luck!

I'd get a convertible seat and a stroller that has a good recline. (Can't specifically suggest anything since my strollers were mostly doubles and triples.)

We had to move to a convertible car seat for our second child much faster than our first because of his size. We bought the new Safety 1st Complete Air Convertible car seat and have been very pleased so far. He went to the seat at 9 months and had no problem transitioning as it still has a nice recline. We also have a britax boulevard and haven't seen too much difference in quality between the two. Also, Graco now does an infant carrier car seat for up to 30 pounds. You could try that one. It might fill the gap between now and when you are ready to go to a convertible.

For stroller, you might look into the Maclaren. There are several that have a good recline and the 5 point harness will be good for the 5 month old too. We love the Maclaren. It's compact, very sturdy, and has a nice size compartment underneath.

My daughter was born almost 11 pounds and 23 inches long. I would recommend any convertible car-seat, but I use the Safety 1st Air which I have linked below.

As for a stroller, I would get a Bugaboo if you don't mind making a small investment. You can find them on Ebay or Craigslist for half the price. For a cheaper option, I would go to any store that sells strollers and see which one is the roomiest.

http://www.target.com/Safety-1st-Complete-Convertible-Seat/dp/B002XLB9F4/ref=br_1_13?ie=UTF8&frombrowse=1&qid=1276797826&searchView=grid5&sr=1-13&node=3579961&searchRank=pmrank&searchPage=1&rh=&searchSize=150&id=Safety%201st%20Complete%20Convertible%20Seat&searchBinNameList=purchasing_channel%2Ctarget_com_brand-bin%2Ctarget_com_primary_color-bin%2Cprice

I am researching convertible car seats right now and these two came highly recommended -- the Britax Blvd and the First Years True Fit (way cheaper but heavier). I just have to see which fits best in our car.

As for stroller, we have the Combi Cosmo and love it. We also have a Maclaren Volo but it doesn't recline. I think the Triumph (the next price point up) does.

My son was similiarly sized at age 5 months. He just turned 3 and is now 42 inches tall and about 40 pounds. Your biggest concern should be ensuring that your son can continuing to rear-facing for the recommended time (now at least two years). I don't recommend the Britax for this reason. The work best for shorter kids. I was really bitter when our second car seat last all of six months.

Graco MyRide, Radian, and True Fit all have excellent safety data and fit tall kids well. Every convertible car seat will have an infant insert that will help support him. The Graco and True Fit are both inexpensive.

A bugaboo does some things really well but it isn't what I would recommend for an infant who is growing fast. The cameleon, which we have, has a weight limit of 37.5 pounds. He was way too big for it by the time he was 2.5. Not much of a life span... Truthfully, we rarely used it at the age but it was a bit of surprise when we tried to one day. I hadn't even thought to look at weights.

you want a convertable carseat for sure. as for a specifix brand, i would just look at those that could be used for the greatest span of height/weight for your budget. look for "3 in 1" in the name of the seat. these seats usually go from infant, toddler, and finally booster all in one chair. itd save you a pretty penny. i do know that eddie baur and safety first both have a seat like i mentioned at a reasonable price.

as for a stroller, ive only ever owned a monsterous evenflo travel system, a chicco umbrella stroller (which was nice but didnt recline), and my current joovy caboose ultralite. ive recently seen chicco has a newer stroller on the market which does recline and is also compact, called the Liteway, and its also in your budget. as far as im concerned, they make decent baby gear. good luck! :)

Another vote for for Britax Blvd! Our huge boy grew right out of the chicco set within 3 months and we've been with Britax ever since. Do a time-cost comparison (that is 22 months going strong with the Britax) and it was a WAAAAAAAY better buy than the infant seat. It comes with an infant insert too!! If you fella is anything like mine, go for an economy stroller...he won't be in it for long anyway!

i also own a sunshine kids radian. love it. however, i dont love the price tag.

My son is very tall for his age and outgrew his car seat based on height very quickly. We have both a Britax Roundabout and a Maxi Cosi Priori. I highly recommend the Priori. It is reclinable, which is great if he is still 5 months old, and it is one of the only car seats that is qualified rear facing up to 35 pounds (I think thats the right weight limit).

Another vote for the Britax Boulevard. We moved our third child into it at 5 months when he outgrew the Snugride, and he's still in at age 2.5, with plenty of room to grow. The Boulevard can be rear-facing until 35 lbs., and chances are, your baby's growth will slow down. Britax seats are so much easier to install correctly than most other brands! For strollers, I would look into the Baby Jogger City Series. We have a double, but my 5-yr-old is still comfortable in it, and my 7-yr-old can still squeeze into it! It's nice and tall, reclines, and has a 5-pt harness.

I love our Quinny Buzz 3....we use a Maxi Cosi carseat that pops on the base but it comes with a great stroller seat that you can angle back to a more prone position (better for younger babies).
It's definitely not under your price range but sometimes you can find really good deals on ebay or other websites as certain colors go on sale.
It was a bit pricey for us but well worth the investment...I love love love it!

The Britax Boulevard was the seat for my tall guy. Easy one-hand tightening and loosening of straps & side head support. We had him in it at 8 months facing backwards and now at nearly 3 he still loves the seat. With #2 on the way, I'm thinking I might buy another one!

I have a chicco key fit 30. It's supposed to be longer so they can stay in it until 30 lbs. (when they can face forward) Either that, or get a bigger carseat like the Britax that you can't take out and snap into a stroller like the infant seats.

My daughter is on the small side (9% height/weight), but at 16 months she seems crowded in her Chicco Keyfit 30 carseat. I've been looking at the Sunshine Kids Radian... model I was all set to buy her a Britax Advocate CS (which you can find on sale for $300 right now at multiple places) But the Radian seems to be recommended more than Britax on car-seat.org, and when comparing regular prices, are not as expensive as Britax.

The Radian XTSL seat also offers the first NCAP tested, high capacity LATCH system up to 80 pounds without the use of a seat belt, and can be rear-facing up to 45 lbs. I really like the high weight limit for rear-facing, much better than the Britax Advocate's 35-lb RF limit.

My daughter is a string bean so I'm looking for tall baby car seats as well - for convertible seats, tallbabystuff.com recommends the Britax Marathon because it has a high weight limit and high shoulder straps and will last longer as a forward-facing toddler seat.

We have a bumbleride flyer stroller which I love but costs $300 . It reclines fully, is fairly smooth, and seems to have a lot of room to grow. That said, my daughter is 7 months and seems just as happy in our cheap umbrella stroller, so if you can hold out for a few more months until he can sit up well you'll have more stroller options.

My hubby and I are both over six feet so we expected a big one - although we didn't really expect her to start out 11lbs9oz. Whatever. We were forward thinking and bought the Graco SafeSeat - it's the same as the SnugRide but bigger. She grew out of the standard size infant seat at 9mo but she's got plenty of room in this one. Graco seems to make room for the bigger babies.

my daughter is a big baby as well--28 pounds and 32 inches at 12 months. I switched out of the graco snugride 32 at about 9 months because she just wasn't comfortable in it anymore.

I got a britax marathon in a discontinued fabric at a great price from albeebaby and a maclaren from gilt. combined it was about 350 for the two. I wanted an umbrella stroller, but so many of them have low weight or height limits. maclaren goes up all the way to 55 pounds and the handles are comfortable for tall parents to push.

you can find good prices just be open to the color options (bright pink suede-like carseat not my first choice, but at the price it couldn't be beat!) and shop around.

and my daughter is very happy in them both.

The Britax Boulevard absolutely lives up to the hype. I got my son's on closeout at albee baby, it looks like they have some patterns on closeout currently:

http://www.albeebaby.com/britax-boulevard-convertible-car-seat-in-moonstone.html

As far as strollers are concerned, I have researched the subject into the ground (like embarrassing, full-on geek-out research). We had a cameleon and ended up selling it. I loved my bug but it wasn't perfect. The weight limit is an issue, it's cumbersome and bulky for storage. For your needs it sounds like the BJ City Elite would be a slam dunk. Baby Jogger strollers have more headroom than most and this model has a full recline. The one second fold also rocks my face off, and it looks like certain colors are on closeout at albee baby (no, I don't work for them, but they should pay me).

http://www.albeebaby.com/baby-jogger-city-elite-single-stroller-in-tan-sport.html

Thank you all SO much - since I wrote in I ended up getting the MyRide 65 from Graco but am still on the hunt for a stroller that can work with our lifestyle. Thanks again for all the suggestions - I'll be doing some hardcore shopping/research this weekend.

(I would have totally recommended the Britax Marathon if you were still looking...We love the one we have and will very shortly be getting a second for our younger child.)
As for strollers, I have had a love-affair with the MacLaren Quest since my 3-yr-old was a small baby. The thing I like about it for taller babies is that although it is an umbrella stroller, it has little seat-extenders that make the seat longer for young babies or for extra-long-legged kids. It also reclines pretty far, but not quite flat. They aren't cheap, they're around $200 (sometimes you can find a deal on ebay), but they are very well designed, very compact, easy to collapse/fold, and they only weigh about 12 pounds so if you're pushing a big baby the stroller won't add to the weight. I love mine so much, I now have a double MacLaren Techno.
One stroller I definitely would NOT recommend is the InStep/Schwinn jogger. I HATE it.

My son out grew his car seat at 7 months. We went with the Maxi-Cosi Priori because it fit in our small cars.

Be sure to check out http://www.car-seat.org/ for tons of car seat information. If you have an questions, that's the place to ask them!

Maybe this isn't a concern, but if you drive a smaller car, make sure that whatever convertible you choose fits rear facing. We drive a Hyundai Elantra, and there were only three convertibles that fit in the rear facing without causing the passenger in the front seat to have their knees to their chin. It is less of a problem once you have a forward facing kiddo.

My son grew out of his Chicco Key Fit at 4.5 months. He is very tall and most of his length is in his torso so the straps actually weren't long enough! We got the Britax Boulevard because it was the best convertible option for us...but you should figure out what works best for your car and your baby.

Strollers...that's a totally other ball game. We have the '09 Uppababy Vista and he is too tall for it...the '10 is a couple inches longer and sits up straighter.

I actually would recommend looking into a small frame stroller that has a recline option for your baby that doesn't sit up yet.

The Baby Jogger City Mini is a great stroller, I have it and absolutely love it -- but I'm not sure I'd recommend it for a tall kiddo. A tall kid will outgrow it before he'd outgrow many other strollers. (Though, because the OP's baby is still relatively small, she probably would get several years' use out of it.) The more expensive baby jogger models have a lot of the same features as the mini, but accommodate taller kids better.

With a car seat, for a tall kid, you need to look at harness height. Many of Britax's seats wouldn't be great choices, b/c their top harness slots are low. Particularly considering their price. I know that Radians and True Fits have higher harness slots than average; I don't know about the My Ride.

Finally, I have to disagree with the suggestion to look for a carseat that's marketed as 3-in-1 -- from everything I've heard, these do not make good booster seats (although they are OK, not great, as convertible carseats).

I know you already got a carseat, but this was an issue for us as that my husband is 6'5" and most people on my dad's side of the family are over 6' tall. We got the Graco SafeSeat like another mentioned - like the Snugride and as well rated for safety, but larger. Fit in the back center of my Saturn SL2 and my husband's Subaru Impreza WRX without issues. When she outgrew it, we switched to the First Years True Fit because it is well recommended for tall babies, highly rated for safety, and unlike many other convertible seats, the cover can be removed to be washed without having to uninstall the seat. This seat also fits well in our car backseats.

As for strollers, no recommendations. We used the Snap and Go with the Safeseat until she was able to hold herself up, and then we switched to a Maclaren Volo and Chicco that was like $35 on Amazon.

The Britax convertible car seats all have really high weight limits, including in the rear-facing position. Can't help on the stroller, as we use the Ergo, even for a big baby.

We have a Britax Marathon convertible seat for our son and are very happy with it. He's 2 and a half and probably won't grow out of it for another year. My brother uses a Sunshine Radian convertible for his *very* tall toddler and gives it high marks.

As for stroller, I'd suggest the Chicco Cortina for price, features, and longevity. It reclines all the way to flat and gives a nice smooth ride. The basket is a good size, and it can take a child from infant (flat recline!) through toddlerhood. The Maclaren Quest Sport is also a nice stroller, light and easy to steer, but better for for keeping in the car trunk and navigating stores, farmer's markets, etc. It's a less roomy seat and our toddler's legs now hang past the footrest.

We got our car seat with a 20% off coupon at Babies R Us (ask at customer services for coupons - they usually have little books of them good for certain dates) and our Maclaren on sale since it was the previous year's model.

Yes- get him a convertible car seat- he will be much more comfortable. We switched our son to one at 5 months. As for the stroller- do you really need one? You could carry your baby in an Ergo or similar style carrier, which can be worn front or back. I carried mine in the Ergo until well over a year old. If you can hold out until he can sit up unassisted (just a matter of weeks), you could get an inexpensive umbrella stroller. Babies R Us has some options.

http://thesweetest3.com/

I've always been happy with our Radan carseats (by Sunshine kids). They are made to go a long way! I put my 4mo in a Radan 80 when he outgrew the infant carrier seat. My almost 4yo is still in his Radan 65 and still has one more height slot to go. (I kept him rear facing in that seat until almost 2yo.) Both my guys are tall and in the 95 percentile for height. They are also slightly cheaper than Britax, scored really well on the safety ratings and have a steel frame which makes them less bulky.

As far as strollers go, we liked our Graco ok. But we also got a Chicco stroller. It's a step up from the basic unbrella stroller as it has a basket and sun shade. It was cheap and has lasted a long time. Again, the almost 4 year old still fits in it.

Baby jogger city elite hands down.