Miaghstir: VMWare Workstation offers 3D-support for guests running Windows XP and above, and possibly for Linux and BSD. I don't know how well it works though. VirtualBox has a similar solution.
Xen offers full pass-though to the host GPU, but only runs on Linux hosts.
That's what i need! My main operating system is Linux for more than half-decade and i fed up with dual booting. Until now i haven't got a powerful machine for virtualization. I recently bought a Sandy Bridge system with a GeForce GTX 560 Ti as graphic card. If it works, i will be great. Windows 7 on a workspace with games =)