I have a Canon Rebel XT, it's a few years old, and really lacking on features and speed. I also have a 18-55mm, a 70-300mm, and a 28-135mm. I am about to get a 50mm 1.4, and I can't wait. I am also hoping by the end of the year to upgrade my body to Canon's 7D. After that I will be done for a bit. The only other thing that I will "need" to have will be the external flash.
As far as results are concerned, I am happy with what I am getting, but after attending Pixelmania! last year, and having a friend like Tim from The Magic in Pixels, I have reached the limits of my Rebel, and really need the 7D to take my hobby further.