Myself, I got a very long curtain rod ( I believe Bed B Beyond had the longest) and I bought 4 curtain panels at Pier 1.
Depending on your size ofcourse , would be nice if you can open them all the way so the curtains hang on the walls instead in front of the windows on the side.

Assuming you're planning to put up shades/blinds, you can find 2 singles (for the sides) and a double (for the middle) that match. I had to do that. At first I was adamant about having one big piece, but that turns into a custom job which can be quite expensive. That said, if you own the place and plan to stay for awhile, it might not be a bad idea. Otherwise, I wouldn't invest that kind of money. Also, if you're worried about it looking too choppy, one set of curtain across all 3 windows will help bring the whole thing together. I would start the curtains from the ceiling to add height, but that's just me :) Also, these days you can find pretty decent shades/fabric blinds at the big home goods stores. They've come a pretty long way since the 80's. Good luck!

To keep several panels from looking sloppy, pay attention to the details. I think that the window could look great with floor length curtains with a single rod - mount it several inches above the window (but not flush with where the ceiling drops on the left - I'd try about 2 inches above that height). Look for panels with tabs or clips to minimize bulk at the top, that way you can push the curtains all the way to the side to frame the center window when opened. With neutral, solid color curtains and a nice curtain rod, I think it could look very tailored and provide a strong backdrop for however you decorate. Or try dark or bright colors for a dramatic, bold statement. Have fun!

I had the exact same problem when we moved into our new house. My entire window is 150 inches long. I ended up installing 3 panels of 2" vertical blinds that I purchased off the shelf at Home Depot,and we installed them recessed inside of the window frame. Heathercan9 is right, you can get very nice blinds off the shelf nowadays. The total cost for the blinds was around $100.

Because of the bulkhead next to the left window, I would get blinds or customize some roller shades with fabric or a stencil and hang those inside the window frames. Then to add some softness I would add 2 dummy panels on the end windows with the rods hung as high as possible in a coordinating color or pattern to the blinds/shades. Dummy panels would mimic the softness of a whole wall of curtains but be more cost effective and not fill your side windows with fabric.

I'm very minimalist when it comes to windows. I love this look, not sure if it would work for you. I purchased huge sheets of architect drafting paper from an art/design store, and the paper was white and semi-opaque and stronger than usual paper - I'm not sure of the exact composition. When I used sticky-tack to adhere it to the windows it looked amazing....just these beautiful white squares of light, but relatively private. You could even put up cut-out black card as silhouettes and make it like a shadow-puppet space for people outside to see.
Pretty different, but that is my kind of thing :)

Personally, I would do roman shades for those windows - 3 separate roman shades so that you have a shade to fit each of the three windows. Nice, clean lines and minimalist.

I have HUGE windows in my place as well. I actually did go the multi-panel route, and I like it a lot. I used a more sheer set in the middle.

I have 2 windows exactly like this. Lovely light all day but we like some privacy at night. I installed an extra long rod with 3 mountings so it would not sag. I used 4 panels of off white curtains and over them on the same curtain rings I added a pale green sheer. The look is etheral and subtle and much richer than one plain curtain.

Ceiling to floor draperies with thin cotton curtains. IKEA has a system celled Kvartal that I've used in my livingroom - drilling it to the roof. You could also do the curtains in two layers with thin white cotton closest to the windows and something sturdier, like velvet, towards the room.

Your solution depends on whether you need to block light or simply provide a bit of privacy. Because of your bulkhead, doing properly full fabric panels with a centre divide will mean narrowing your window when they are open. It's also a pretty dull, traditional look. I've done multiple divide panels before in a giant window and hated it - too fussy, constantly adjusting them to divide evenly when opened.

We have similar giant windows in our (tiny) living room. The windows are almost always in shade, so light blocking isn't an issue. I put up one (el cheapo) rod with pocketed sheers (4 x 54" to get a medium fullness when closed). They end right at the edge of the window, midway between ceiling and top of window, which would solve your bulkhead problem. My walls are ultra white, and the sheers are ultra white - for our home this is a good marriage of our modernist style with some softness.

If you need to block the light (ie for heat reduction), I would suggest 3 roman shades with a bit of fullness or with a decorative pattern for visual interest, with a light-blocking backing (this can be DIY, I think a tutorial is on here?). Use hzi's trick of putting up a translucent panel for privacy along the lower 1/2 aligned with the top sash of your side windows when you want the blinds up for some sunlight. (You can also get faux glazing vinyl rolls at the orange box store - I've used this in a bathroom window and loved the effect).

Have had many similar large windows to cover. Home Depot & Lowes have round trim, long enough to cut to the correct size, paint white. Ikea sheers and drapery panels - as well as Walmart drapery panels - are very inexpensive and fool everyone. Good luck with your new place!!

I have a very similar length window in my living room. I bought 2 packages of these (in a different color)
http://www.lowes.com/pd_42191-73-23-7502-77_0__?productId=3033367&Ntt=curtain+rods&pl=1&currentURL=%2Fpl__0__s%3FNtt%3Dcurtain%2Brods%26page%3D2&facetInfo=
and instead of screwing the finial onto the end, we removed the screw from one side and put the two rods together. As long as they are supported sufficiently they look like they ae all one rod. Added four panel curtains from pier one. It looks very nice. Before that we bought two really big drop cloths and hung them like curtains. Cheapest curtains ever.

I have this same window. White faux wood 2" blinds hung inside the windows look really good. You can get the right size at Lowes so don't worry about custom cost. I want to keep the area non-fussy so panels are out for me.

Three panels of Bottom -Up blinds in a simple off white fabric would look nice and clean. This will allow light to come through and privacy.
My friend has these in his apartment which is a similar layout as this and they look great.

You can look around for a custom blind shop for prices, they were not that expensive and easy to install.
With blinds you will have room below the window for a low credenza or some furniture.

For drapes you would need a lot of fabric to do it right which would be very expensive and more of a commitment in terms of style, color and cleaning.

example-http://www.bottomupblinds.org/wp-content/uploads/Bottom-Up-Blinds-22.jpg

I have this exact same problem. I'm liking the off the shelf shade suggestions, might check that out as a backup idea.

I was actually planning on spending the money to have 2 large panels custom made. Because our window lets in so much light I would be opening and closing these curtains often, so seperate multiple panels would be a huge PITA to rearrange every day. As a Cheapy McCheap option I was considering buying 6 or 8 nice grommet top panels when they are like 90% off and then sewing them together to form 2 very wide panels. Has anyone done this? Does it look terrible?

1) Get a giant curtain rod and four luxurious looking curtain panels.
2) Inset the actual window frames with shades to your taste. Grass/bamboo, roman, solar, etc.
3) Enjoy your classy window treatments.

Living in a historic house, I had huge windows to drape. I scavenged bargains at local department stores and picked up my curtain rods at a moving sale. Those are my recommendations, because buying cheap blinds would upset me every day I had to look at them.

Forgot to add: JC Penney has good sales on window treatments at any given time. I just got rods and panels for a guest room at 50% last week, so check them out.

I saw a solution in House Beautiful that I loved: bamboo Roman shades on the windows, then full-length floor to ceiling curtains w/curtain rings - very full - that ran almost wall to wall. Really gorgeous. You can certainly use more than one panel; just sew them together. Will work fine with rings, clip-on or sewn.

Customized honeycomb shades from big box retailer, smith+noble or other online shade store.

My LR has the same window set up. Finally - after a couple years with no blinds - got 3 of these to go over each window. They are full privacy but let some light through. Got them in natural, but also a white one for another room, and they are both nice. And, as luck would have it, perhaps the cheapest option we ever considered!
http://www.countrycurtains.com/product/400+roman+shades+and+roller+shades/403+roller+shades/040547309+textured+woven+shade.do?sortby=ourPicks&filterby=

The front window of my apartment is almost exactly the same. It's 11 feet across, but the longest curtain rod I could find was 10 feet, so I got a round dowel from Home Depot to extend it a bit further. I used 5 sheer cream panels to the floor, for privacy, yet to let light in. (I should have used 6. I'll get another one after I have my Xmas money.) The panels themselves are patterned, too, because I hate the mosquito-netting look of plain ones. Then I put holdbacks on the sides for when I want to open the side windows in warmer weather.
Good luck!

I would hang floor-length shutters from a ceiling-mounted track. Have several overlapping tracks so that you can slide them all to one side or the other when you want light. It doesn't have to be shutters though. They could be fabric stretched over a rigid frame, shoji screens, etc.

My tip would to be that you don't treat these windows like a single window... break them up in a way that's similar to their current placement! It won't look cluttered, especially if you can balance it... I'd suggest buying two panels of one type of curtain, and then buy two panels of a different, somewhat corresponding curtain. You can put one set of the two matching panels over the big middle window, and then put one of the other panels over the left, and the matching one to that over the right. It'd add interest to the room, and it'd look nice! I'd also suggest staggering the bars (and buying three separate bars--one for each of the windows), so that the two smaller windows have bars that are lower and the middle one has curtains hanging higher. It'd look nice! But inevitably the decision is yours to make. :)