I recommend buying the best camera you can afford. Don't be bullied into getting a Rebel by posters who claim that a Rebel is the camera that a newbie should get! You can shoot a 7D as simply as a Rebel but, you won't grow out of an x0D or 7D as easily as you might grow out of an xx0D camera.
Although many photographers are happy with their xx0D cameras, I could never recommend purchasing one. I just don't like the series at all and, much to my regret, I once owned one.
I will agree that "equivalent" xx0D models will give you image quality similar to the equivalent x0D camera. However, among other things, I like the controls, the viewfinders, the faster burst and cache rates, and the larger size of the x0D cameras. I would prefer to purchase a refurb or even used older x0D camera to a new xx0D model.
ONE POINT IS CERTAIN: The lens has the most influence on the quality of imagery you attain. The quality of the lens is far-far more important than the model of camera which you shoot. IMO you would get better quality imagery using a 30D or 40D camera and a top-line lens than using a lesser quality lens with a 7D.
