These trees look like "charmes pyramidal" or "Carpinus betulus 'Fastigiata'"

http://www.jardindupicvert.com/4daction/w/photo_plante.phspliol?session=9594y77m4p67a&nopl=4486&p_cour_c=1&indexpl_c=1

^^ Agreed. Fastigiate European Hornbeam. There are a number of species with fastigiate cultivars including oaks, tulip poplars, and maples.

Charmes (in french) are fast growing but very tolerant of being cut and they are very well suited to topiary. Their foliage is marcescent (do not fall in the autumn but at the end of winter).
Unfortunately the winter foliage is not very decorative. By cons, in the spring, new leaves are a beautiful green spruce.
Sorry for my english...

Be careful about the bamboo - some towns require a permit in order to plant bamboo because they can become extremely invasive. I think black bamboo is the worst, but I'm not sure. You might be required to dig a barrier to prevent the bamboo from going into neighbors' yards.

Hard to tell what those trees could be without a closeup of the leaves. They might be some sort of ornamental fruit tree. I am guessing that this is their fall color.
You should go to your local nursery and talk to them about what grows best in your area and what they recommend for the conditions in your yard. Is your soil wet or dry? How much sun do you get? Is it morning or afternoon sun? Is the site windy? How big do you want the trees to get? Do you want spring blooms? Fall color? Are you or your neighbors going to be bothered by fruit dropping out of the tree? Or maybe you want a fruit tree?
I would recommend looking into native trees because they are usually hardier and accustomed to your conditions.
Some Bamboos are considered invasive in some areas, you should check on that too before buying.
How close you plant the trees depends on how big they get and how much privacy you want. Since you are looking for more of a hedge effect, I would plant them pretty closely.
You should also look into large shrubs, they don't have trunks, so you have greenery closer to the ground - if you want to hide your fence, that might actually look better.
And a word of caution: I would recommend against ordering trees online. I couldn't resist an offer for a dirt cheap tree and received a six foot stick with no branches that my neighbors dubbed the "fishing pole tree". You get what you pay for.....

DON'T DO BAMBOO!!! It's like mint on steroids. It will take over everything and it's quite distructive.

Some types of bamboo can crack a foundation.
The best course of action is to take the photo (and others) to a reputable garden center and describe what you are after. They should be able to recommend the best species for your area that will effectively do what you want them to do. They should also be able to give you care and pruning tips.

To me it looks like forsythia that has been trimmed in a specific way

I agree with the other commentators that is definitely an hornbeam and possibly a 'Fastigita'. But, if you can find it in your area I'd advise you to choose the Carpinus betulus 'Frans Fontaine'
http://www.vdberk.co.uk/tree/carpinus-betulus-frans-fontaine
because the 'Fastigiata' does grow and than you have a problem.
http://www.vdberk.co.uk/tree/carpinus-betulus-fastigiata

If you can't find the 'Frans Fonataine' than you can opt for clipping. Than I'd advise you to get a straight hornbeam. . It looks better and most probably would be cheaper (I don't know how is with the prices over here).

In UK the winter foliage, especially if the trees are clipped, doesn't actually looks bad:
http://www.townplacegarden.org.uk/Images/Horn-Walk-09.jpg
In northern Italy on the other hand looks bad.
I think it depends if the plants get stressed by draught in summer or not. I don't know how is in your area.

Do not plant bamboo!! You WILL regret it and your neighbors may regret having you as a neighbor after it gets 'established'!

My first thought with that brilliant shade of yellow of the foliage was a ginkgo, but a hornbeam also makes sense.

Either way -- DO NOT PLANT BAMBOO. I repeat: do not plant bamboo. It takes over completely and you ultimately regret it but you will never, ever be able to get rid of it.

I agree with a big NO on bamboo...my neighbors have it and it's completely taken over (and knocked down) the fence between us and grown through my yard in the 5 months I've lived there...

My guess was that the trees are ornamental pears, also known as flowering pears -- they have a similar shape and autmn color. The chanticleer variety has a fairly compact and upright habit, like the trees in your photo. Pyrus calleryana 'Chanticleer'

Are you looking for colored foliage year round? Or just spring/fall interest? How tall? Upright shape like those? I hesitate to plant anything "big" that close to any kind of building foundation or plumbing/sewers - roots can cause so much more damage than you'd expect!
Look for natives, be realistic about maintenance (don't plant a tree that gets 30' in a 15' spot and expect to just trim trim trim - it can be hard on the tree and a lot of work for you). Check your exposure (how many hours of sun? lots of wind or protected? dry soil or soggy? clay, loam or sand?) and then go to a good local nursery. Tell them your conditions (bring a few photos if possible) and your wishlist for size/color/flowers/fruit and a good nursery can help you only have to plant once and help you keep maintenance down!

re bamboo - isn't there noninvasive types of bamboo? I recall doing research online on clumping v. running (invasive) bamboo.

there are clumping bamboo that won't spread. it goes up but not out. the root system stays contained.

I don't believe the so called non-invasive bamboo is truly non-invasive.
The only bamboos that grow in Zone 5 are all horribly invasive.
DO NOT PLANT BAMBOOS, ever!!!
Yes, please listen to the wise sages above.
And also, the tree suggestions are all good ones and probably spot on.
Pruned forsythia they are not.
Another tree to consider is the columnar Bradford Pear.
It maxes out at about 6-8' wide by about 16-20' tall...would that work in your spot?
They're not fussy about conditions other than full sun (meaning 6+ hours or more of direct contact sun).
And yes, of course take this photo with you to the nursery center and explain what you want.
Find out where the landscapers get their plant material and go there.
Good luck with your project!

If you like the look of bamboo, but are worried about it being invasive, you can plant it in containers. We have large, rectangular troughs planted with bamboo in front of a willow fence. It looks good year-round, gives privacy without blocking sunlight, and makes that lovely rustling sound when the wind blows. You do need to water regularly during the dry season, but it is hardy (we're in the UK, where it falls below freezing in Winter) and it grows fairly slowly in the containers.

I also think it is a type of hornbeam. We have something very similar as street trees, zone 5. They don't get terribly tall and have a naturally compact shape. I like how these are limbed up and provide structure.

oh my. calm down about the bamboo, people. there are different varieties of bamboo, and not all are extremely invasive. The extremely invasive variety CAN be contained also, it just is a bit more legwork to install --- you have to trench and put in an underground barrier to contain the roots. (instructions from Mike McGrath of You Bet Your Garden: http://www.gardensalive.com/article.asp?ai=608) With that in mind, underground barriers can be a pretty fascinating tool to use --- if you visit Grounds for Sculpture in New Jersey, there is a fabulous piece of sculpture made of bamboo, like a bamboo cave thing that you can walk through, and that was done by containing the roots in an underground design. Pretty fabulous. (Grounds for Sculpture: http://www.gardensalive.com/article.asp?ai=608)

it looks like poplars to me, I dont know which specific subspecies though. I agree with everyone else, stay away from bamboo....

My only concerns is that in planting the trees this close together, you're going to have to replace them fairly frequently (every 3-5 years) as their roots grow together and they crowd each other out or get nutrient starved. you might be better off in that instance with potted trees that you could then plant elsewhere or sell and replace when their roots get too big. Way easier than digging them out.