suteck :
If cannibalized means you're going to reuse the psu then make sure it has sufficient power for either graphics card along with the proper and enough connectors and/or adapters. If you're using adapters you will also need to check that you have enough plugs for the other components once you have the card plugged in. Make sense?
Thanks, suteck. Yes it makes sense and I've worried about it. I had read that 400w should be enough for most budget systems, so the link to the spec sheet does give me pause. What I think I'll do is look at the assembled goodies and connectors and see what the body count is like first. If worst comes to worst then, the power source will probably be the first upgrade - a good 80+, 650W item.
As I mentioned to bavman, he may be doing some CAD on it and his brother, a photographer, may occasionally come over to use some of the bits as well. I'm pretty tempted to stick to the hexcore for that, even though my understanding is that the multicore software for single threaded applications is ... less than brilliant.
I agree that AMD is much more consistent than Intel, and I've had my fair share of both - I'd just read that they were thinking of a significant move when the new architecture came out. Still some backward compatibility, but essentially requiring both a chip and mobo refresh over time.