I just bought myself my first camera, a Rebel T2i. I knew a decent amount about the Canon lineup before making my decision, but never really paid much mind to the 1.6x crop factor that most of the cameras have.
After doing some calculations:
A 50mm 1.4f lens on a 1.6x body gives you equivalent results to an 80mm 3.6f lens on a 1.0x body. Not in terms of amount of light captured, but in terms of your DoF results.
You basically diminish the beautiful DoF effects that you pay so highly for in expensive lenses by not having a 1.0x body it seems.
So is it a big mistake buying up these 1.6x cameras? Seems you lose a lot of shallow DoF potential by doing so. With the amount of megapixels on cameras now, you don't really lose out on much if you decide to 1.6x crop pics from a 1.0x body anyway.