I recently was looking for a solution to run WinXP on my Linux debian system, since wine did not worked for me. I had to give up on kvm since I do not have the proper extension, I was then slowly looking into XEN...
Until my attention was brought to virtualbox:
This looks like the perfect solution, I am not a big fan of vmware and there is a debian package for virtualbox :)
There is no USB support in the debian package apparently, you need the commercial version :