CONROE VM Test machine any advice?

Looking to create a Conroe/Woodcrest test server/workstation for software development using either Xen, Parallels, or VMWare ESX.

I'm thinking of either going with a Conroe E6700 w/ 4GB ECC on an ASUS P5W DH Deluxe, or the SuperMicro X7DBE+ board, and go with 8x1GB FBDIMM ECC modules to start, with 8 empty slots, and put 2x Xeon 5148 CPUs.

Basically, the idea is to create a clearly overkill machine, but that has test database, web, asterisk, etc on a single machine, all running emulated for the sake of resetting test conditions, yada yada.

Reason why I am not interested in getting a bunch of cheap boxes? Because I don't want all the physical space, heat, etc all with different hardware and drivers. I just want to get it working with the VM drivers in the emulator, and then only maintain the host OS.

Anyhow, advice is welcome from people who have experience.

If you don't know what the heck I'm talking about, please find another thread to post on.

Thanks ahead,

John