Windows Virtual PC is in beta. I love the integration it has with Win7 (running VPC on Win7). It makes it seem almost like it's part of the OS.

I use VPC at home and a mix of VPC and VMWare at work. For what I'm doing, the functionality is equivalent, but it takes VMWare much longer to boot up and shut down.

>Yes, there are others beyond VMWare and VPC, but VMWare seems to be on top of the pack for now. I'm sure M$ will come on strong - they do have the advantage of billions in the bank and the control over the OS, which they don't hesitate to use to their advantage.