Good choice for PSU, it's the exact same one I'm running right now on this comp, and it works like a dream. However, if you can find it, I wholeheartedly recommend a Tagan 480w PSU; it's 12v rail is pretty staggering for its price (in the UK anyway).
Newegg don't seem to have the Zalman CNPS7000*B*-Cu variant, which works with socket 939. If you can find it though, it's definitely a great buy, works very well even on its lowest speed setting.
Lastly, I picked up the 6800GT over the ATI competitors mainly because of the OGLbenchmarks, and the support for pixelshader 3.0 (although whether it's need or not currently can be debated). Plus, you can overclock it to Ultra speeds, if you pick one up from a decent brand. You could do the same with an X800 pro to XT, by modifying 12 pipelines to 16 I think), but it's a complicated task.