A lot of people have been recommending GTX 460's but I would suggest the GTX 470. There have been a lot of great deals for the GTX 470. I got mine a while ago for $250 after rebate. You can easily find them for only about $30 more than a GTX 460 1GB version. The performance boost is significant, especially on higher resolutions. Definitely get a GTX 470 if you can find it for around $250 to $280. However, they do run pretty hot and their fans are loud at higher settings so you need a case with good ventilation.