Overall, pretty good, it certainly will hold out for a couple of years without any additional stuff.
Processor: I wouldn't have got that one, personally I would have gone for the Intel Q6600 (2.4GHz, Quad Core). There aren't any compatibility issues (some people have thought that), and you get in effect 4 processors instead of 2 (even though the dual core ones have more power (3.16GHz), there are only 2 of them meaning total you get more from the Quad).
RAM: 4GB: Futureproof for ages to go yet. That will be the last thing you need to replace.
GFX: ATI is a different way to go with nVidia dominating atm, but it will do well. I would have gone with an nVidia 8800GT, as they are coming down in price, will do just as well, and love to be overclocked.
The Rest: All fine, I would be happy with Vista, so don't worry.