Virtualbox.
Virtualbox doesn't solve the problem of performing non-work related tasks on a corporate computer. It would help resolve some of the concerns about sandboxing data, but only some.
It leaves no traces on the host, so your work is invisible. Just encrypt it and there you go.
I can certainly see that as a valid point, but my laptop is (fortunately?) my own. I wouldn't really want a company issued one, since I have no intention of ever spreading my workflow to multiple machines. As for viruses I honestly haven't had one since I last was using Windows as my main OS around 2007.
EDIT: Of course, I'll acknowledge that not everyone can be in the position of dictating what they use for work and requirements my force you to.
The risk / reward ratio is just too high.