I totally agree with morgstormhammer. Unfortunately, my friend just blew hundreds of dollars for x800 Pro on ebay. He didn't ask me for opinions in advance. I just said the best card is ATI. And he's looking for a 680W PSU. Talk about overkill. Can't wait for him to sell me those parts for real cheap when he gets bored of them.
For me, I would just get an AMD64 s939, 3000+, 1gig ram, same ol' maxtor hd and lg dvd burner. Above average air cooling. All in black. As for video, the most-bang-for-the-buck would be 6600GT. Not very behind of 6800 or x800 in benchies, but for HALF the price. Still, 6600GT isn't worth two hundred bones to me.
If I were to build the ultimate gaming machine, I'd just pick up Xbox, PS2, etc. And Xbox2 is coming out later this year. PS3 next year. All in the comfort of a recliner or sofa. Online? Yep. No BSOD's and drivers to deal with.