Chances are that you haven't heard about VirtualBox. It is yet another virtualization environment, but it has some great features. It has support for Linux/OSX/Windows as the host OS and Linux/BSD/Windows/etc as guest OSes (both x86 and x64), it supports 3D (via OpenGL) acceleration, and it's free to boot! I highly recommend it. (It even plays nice with Windows 7!)

http://www.virtualbox.org