Is any of this mission-critical? If so you want ECC memory. That means xeon or opteron and ECC dimms. Forget the i7.
Is 8 gigs really enough memory for the VM's you're hosting? Also, if you're going with an LGA1366 CPU (xeon 3500 series in this case), you'll want to get DIMMs in multiples of 3, for performance reasons (that means 3, 6, 12, or 24 gigs of memory). If you're positive that 8 gigs if enough, you could save some cash by going with a xeon 3400 series and LGA1156 board, and getting 2 or 4 ECC dimms.
Do you need 2 IO controllers, or just two NICs? There's plenty of 1U boards with two NICs, such as the supermicro you linked.