Desktop virtualization is a must for techies. Serious tools for testing and running multiple workloads on your workstation. There are 2 main competitors in this space the first and most awesome is obviously VMWare. Virtualbox is the next best thing to run on Windows. Windows Virtual PC on the other hand does not even support 64 bit virtualization. Until Windows 8 comes out, virtualbox is your best free alternative. With Windows 8 Hyper-V is going to be integrated on the workstation versions of the operating system as well which is awesome, however main thing that lacks with hyper-v on the desktop is the integration features. One thing I loved with Virtual PC 2007 back in the day was its speed, sleeknes of its interface and the integrated copy paste and file drag and drop. This feature was removed for Windows Virtual PC and is also non-existent with hyper-v.