Ubuntu Feisty with Wine and Cedega for FPS games. I have no interest in DX10. I am usually too busy playing the game to stop and gawk at the scenery.
I also no longer use anything Microsoft. I decided to stop paying someone for the privilege of squashing "their" bugs. I have dual booted for years, but I have spent the last several weeks trying numerous different hardware configurations, and several distros of Linux. My main machine now uses Ubuntu Feisty, and my spare machine is for trying out other Linux distros.
Interestingly enough, after all the hardware reconfigs and OS installs, I never once had to ask Microsoft's permission(reactivate). At least not until I built a third machine from the remaining components, and installed my only copy of XP. I had to call India and ask the nice lady for permission to reactivate one last time. This machine is now doing good work at a local charity. I am also mulling over employment opportunities in the Linux arena.