I bought the 40D last week since the price dropped to the point where it's affordable and I could justify the splurge.
Anyway, it's a huge upgrade to my XTi, simply in terms of the autofocus capabilities.
I played around with it in severe low light conditions (indoors, dim) where my XTi suffer in terms of trying to autofocus. But the 40D has very little to no problems acquiring focus.
I'm still keeping my XTi as my secondary shooter, but I am definitely glad I bought the 40D.
The heftiness compared to the XTi is pretty cool, too.







