Yeah, but he is pretty stubborn, and He Doesn't work, he lost 50$ and he's doesn't have alot of money.. I can't believe he bought his Comp from Bestbuy..
so 4670 it is
9600GT will work (i use in Hp q6600 based system with 300 watt). Good card.
hd3850 will work (no overclock cards). HD4670 is also excellent choice.
Your friend should wait for HD4770 to re-appear. This card is best choice. Because it uses smaller fab process it draws much less power than HD4850 with close to performance.
See last page of article on "best video card for money" on Tom's for relative performance of all video cards.