Which Windows XP runs best on Virtual Box?

[CyberCrone]

I've been researching options for running Windows on Mac Mini with Lion but since each option seems to have as many detractors as advocates, I'm gonna start with Virtual Box because I can't get out of the cost of a version of Windows and Virtual Box being free is a big attraction.

As for Windows, 7 is too pricey so I'm considering XP not only because it's much cheaper, but because I know for sure all my Windows software will run on it. However, there are several versions of XP (sigh). Can someone tell me which version to buy? Ideally, I'd like to hear from people who are running XP on VB and having good experience.

[Sasquatch]

I got an XP VLK, so all I can say is that it works fine. As for the licensing for a single person, you have to get the retail edition. That's the only one that is allowed to run in a VM. OEM aren't allowed.