rjblanke said:1900XT for sure. Just got mine Open Box from Newegg for 359 last week. Just keep an eye on it, they go fast at that price. I used to use a 7800GTX, and the image quality of the XT is much better. I had my doubts about how noticable HQ AF would be in game, but its definitely worth it.
Once you've seen it first hand hard to go back, even if means enduring a little choppiness now and then.