Assuming that you are starting with photography I would suggest the rebel and get good glass.
I'm debating the 50d vs 7d, but that is because I need some of the 7d's features (video specifically, t1i's video is not comparable).
Anyway if you've never used an slr/dslr the 50d will probably confuse you. Do you know about the technical aspects of photography; shutter speed, iso, aperture, dof etc. If you don't than you won't really benefit from the controls of the 50d. Image quality is about the same between the two.