All three use exactly the same sensor and will output the same image. Which one you choose between those three will depend on your personal budget, photo/video priorities, and how/what you'll be shooting.

For most skaters looking to primarily shoot video of skating on a limited budget, the 600D will be the best choice, and the 7D the worst.

The 60d is a good balance between budget/performance. It's pretty much the mid ground between the 600d and 7d. Personally, I use a 600d and I'm very happy with it, although I COULD use the extra fps of the 60d for shooting sequences. For video, the 600d is fine, and a match to the other two. As Al says, it all depends on your priorities.

i prefer Canon than other brand of camera

the 60d is good for filming because it has a swivel viewfinder instead of the fixed lcd screen. the 600d has the same and its a bit cheaper, the only real difference in features it seems is the 60d has faster shutter speeds, faster aperture speeds, and high fps for continuos shooting. the 60d is 999 body only, the 600d is about 850 with a lens. video features seem the same.

honestly the 600d seems like the best bet. the quality of the 60d doesn't warrant the price increase and lack of lens. even though the kit lens isn't the highest quality, it gets the job done, has a good range of view, and will save you a few hundred bucks.

Most of you would hate me for saying this but look into the Sony A65... Cost less then the 60D and in my eyes is better, the stats don't lie.

http://snapsort.com/compare/Canon_EOS_60D-vs-Sony-A65

Sony just doesn't have the lens range (new or used).

Yup. Sony's also lack manual control in video mode, I believe, which is a big no-no.

If you're just shooting video and are willing to do some research/fiddling to get the absolute best IQ, consider the Panasonic GH2.

My 60d has 2 bad drops the first one was from about 4 feet up onto direct cement. And the other was onto hard dirt at about 30 mph. It is worth spending the extra money over the t2i/t3i if you ask me.

The 60D i use at work has been dropped out of a car and lightly dragged on the road while attached to a leash at 40mph. the only damage it took was small scratches to the corner of the open screen.

they're super durable for the price. The 7D would be even better.

So, in summary, dropping your camera equipment out of a moving car is the litmus test of durability

Humphrey told me his 5D got ran over by a car when it was in his backpack, all it did was some cosmetic damage.