This is a long winded post, i know but here goes:
When I first started out I bought my rebel XS with the kit lens and a 50mm 1.8.
While i loved the sharpness and bokeh of the 50mm compared to kit, i ended up using the kit lens more simply because it was more versatile.
50mm on a crop body has the same view as a 80mm on a full frame, i.e it's very tight. While it's great for portrait photography and situations where you can step back a lot, it's difficult to use in many group/indoor sessions (at least that's how i fared).
If it's going to be your only lens maybe try the Sigma 30mm 1.4 (FANTASTIC lens when you get a good copy, but you may need to return one or two till you get a good copy), or if you want to stay with Canon maybe the 35mm f2 (same league as 50mm, just wider).
Simply put, i'd go with a wider lens and crop as needed on the computer. The T2i is 18MP, which should give you plenty of wiggle room. I'd prefer that route rather than missing a shot since I couldn't step back and the subject was too close.
Regarding the T2i itself, it's a great camera. It's what I'm using now. Regarding pricing, it seems to me that there are many great deals out there right now. Today is boxing day sale where I am so there's a bunch of cameras and gear on sale. Maybe that's true for you too?
Edit: I read in another thread that supposedly the T3i is supposed to come in 2-3months. Ugh, I, personally, would buy it now. With the holiday sales and everything by the time the T3i comes out the T2i would be marked at a similar level as they are now. It's not worth it, at least to me, to lose 2-3 months (maybe less, maybe more) of experience and photos to save an extra $50.