PLEASE don't get the Radeon X800XL. It lacks the proper shaders for DX9 games (Shader Model 3), so you will be stuck playing them in DX8.1 mode. While some here will tell you to get the X800 because they will look good even in DX8.1 mode, I tend to believe that you don't buy a card that expensive to not play the newest games on highest settings. The card I suggest is the Nvidia GeForce 6800 GT, which is the same price, and does feature Shader Model 3, so you can take advantage of DX9 features such as High Dynamic Range Lighting, Parallax mapping, Specular lighting, high-res water, and many more advanced graphical features.
