I have a 3850 I got for $90 and I'm very happy with it, though there are a few better options now...I'd go for a 3870, a very good 8800, or maybe the 4850 if you find a deal.
LEFT4DEAD411.COM
Bet with disolitude: Left4Dead will have a higher Metacritic rating than Project Origin, 3 months after the second game's release. (hasn't been 3 months but it looks like I won :-p )