Well if you still haven't totally made up your mind, I am going to tell you right now:
There is no difference in quality between the T2i and T3i
The only feature I found on it that was worth spending an extra 100 dollars over the T2i was the flip-out screen. You should save 100-150 dollars and just get the T2i if you want a Canon Rebel, unless you don't mind spending a little more. Their really is no difference in quality. However, their is a difference between the T1i and the T2i. Don't go T1i unless your budget is tight.
The T2i, if you really work it, can push out incredibly professional results. Here's a photo I took with the T2i and a 28-135 Ultrasonic IS lens from Canon.

If you want a ridiculously awesome camera, you should go Canon 5D. It's a full-frame sensor, GORGEOUS photos (way better than the T2i/T3i), and many pros use it. It's the cheapest full-frame camera Canon has (i think it starts at $1200.00 for just the body), but that is one amazing camera.