you can overclock the C2D very easily. Ive got my e6600 at 3.4ghz and it is FAST. If your afraid to overclock (no need to be but i was a scared at one point too), then all you need to do is increase the fsb just a little to reach 2.66hz (e6700 speed) without upping the voltage either meaning no life taken from the processor. And you save alot of money.
The 600w version is PLENTY.
The asus commando is the same thing as the p5b-deluxe to me. Its supposed to overclock better but i haven't even reached my p5b-deluxe's potential yet so i don't count it (unless you were on phase change
The p5b-deluxe is a solid mobo.
Shoot for the 8800gts. It is dx10 ready (seeing as you are getting vista i would count that as a plus) and it beats the 7950gt.
Here is a benchy
and yes it is ok to drool