5770 would be nice but this is a better buy imo this would be a much better deal for the money:
MSI GTX 460 768mb Twin Frozr II SOC $150 w/free shipping up front, and $130 AR:http://www.newegg.com/Product/Product.aspx?Item=N82E16814127519
768mb is not very much VRAM though, I would stick with a 1gb card. Even a hd5830 would be better in my opinion. If I were him, I would get a hd6850 or a hd5830.