If you want to work with Virtual Machines on one loaded up desktop computer, Hyper-V on Windows 8 is a excellent solution. Be sure to get 2 NICs and follow best practices about only binding one to a virtual switch. On my desktop box I am able to run 4-5 VMs and still play Skyrim effectively. I've run Xen on the same box, and Hyper-V under server 2008r2. The Windows 8 implementation of Hyper-V is reliable and easy to use and leaves you a high performance desktop as an added bonus.