Best Graphics Card for Linux

Im planning on buying a new graphics card for my computer. I ONLY use linux. I play quake III, enemy territory, war craft III, and when Doom III comes out ill be playing that. I am also working on my own graphics engine made in OpenGL. I was thinking of getting the nvidia FX 5900 ultra but I just read the review at OCAddiction.com and according to it the ATi Radeon 9800 is a better card. All those tests were done on win xp and mainly with DirectX stuff. In the one OpenGL test they were about tied.

I was if anyone would know what would be better for me or a place were I could find this out.

Thanks

Nuke