virtualbox.org

I have a corporate laptop, and I have a choice of either XP Pro, or Vista. I know Vista is considered a memory hog, but I don't know if the age of XP wouldn't present other concerns. I'm going to be running the VM's off of an external SSD drive. I'll be virtualizing Windows 7, and probably Ubuntu. Anyone have any recommendations on which host will provide me w/ the best performance?

I have no problems with Vista as host. I have Vista small business and can and do have 4 to 5 VMs running 24/7.
So that would equate to having 6 separate computers running at the same time in one box.
(3) of them are Linux LAMP servers.