Well, I felt that the issue w/ my 40D was the (limited) 9-point AF. I don't know if Digic III vs. Digic IV would have made a difference there. With the 7D (I can expand), w/ a 5D2, there are hidden assist point in the center, and w/ the Nikon AF (I can only assume the closely positioned AF points are more beneficial and can only help, not hurt for tracking).
D7000 sounds like a great little performer and worthy of praise. If I was starting fresh and choosing between Canon/Nikon at that price range, the D7000 would most likely be my pick.
However, as you noted, there's certainly more to photography than what camera body you're shooting. Because ultimately, you'll end up with a lens line-up. So before you decide, think beyond the camera bodies and look at what lenses you might want. After that, then decide on the system and go from there.
Whether it turns out to be Nikon or Canon, at least you had came to that decision being well-informed.