Need help for new build for friend

[Riverslide SS]

hello, a friend of mine, want to build a new computer he wants this :
Case : Gigabyte GZ-X1
Motherboard : Gigabyte GA-P35-DS3P
CPU : Intel Core 2 Quad Q6600
Memory : Corsair 4GB DDR2 XMS2 PC2-6400C5 TwinX
Graphic Card : ??? a ATI HD 3850 maybe 3870 price around $180 - $220
Power Supply : Corsair HX 620W ATX2.2 Modular
HDD : Western Digital Caviar GP 1TB SATA-II 16MB Cache – OEM
HDD : Western Digital Caviar SE16 640GB SATA-II 16MB Cache – OEM
DVD Drives : Pioneer DVR-115DBK 20x DVD±RW IDE Dual Layer ReWriter

so witch graphic card ?
the power supply maybe 520w ? or keep the first choose 620w
that will not be for gaming, gaming will be an option, means maybe sometimes. so something witch he can play if he wants too but will not be games like crysis lol so i thought about a HD3850...

 

[Automata]

This card would work pretty good:

http://www.ocforums.com/showthread.php?t=554903

The HX520 should handle that with no problem