> The 7D is a lot more money though.
Not really, one of the reps that visits our lab bought his for £750 new and the same vendor has them for £670 now.
It's not really an issue of cost. No one really buy "what they can afford", you buy what you're going to get value for money for. It's a hobby that occupies a small amount of my time. I'm just not happy with the pictures from my 400D and want something better.
The 7D is a red herring. I don't want one, and a few 600/650 vs 60 threads have gone sideways when someone suggests the 7D.