Check out HP's DL-585 Server.  Pure processing power with it's four 64-bit AMD Opteron 880 dual-core processors.  It has highly expandable memory and four teamable 1 Gbs network adapters.  All of which makes for an awesome virtualization host server.

Want to know more?

Check out Don MacVittie's article on CMPnet.asia where he goes further into testing and observation mode.

Read it, here.