The idea was to make the autobuild system hardware independant, which I think we achieved, however I wonder if it was worth the extra effort. I think it will be beneficial in the long run since the build is dependant upon the following apps/tools which are not is source control: .NET 2.0, a local SQL Server 2005 instance, CruiseControl.NET, and Perforce.
So far I'm pretty impressed with Virtual Server, especially the ability to mount ISO images directly to the guest CD drive. I can't believe I haven't used VS before today.
The only strange issue we ran into was a "VMRC Negotiate Authentication" problem. Everytime we tried to reconnect to a instance authentication would fail. Setting the authentication mode from Automatic to NTLM fixed this issue for us.