Very frequently I have the need to use a Windows XP machine remotely, this virtual machine is set up on my local server so I don’t really run a GUI all the time on it.  So what I’ve done is (using the GUI) set up VirtualBox, installed / configured it then shut it down.  To bring the machine I made a quick bash script:

#!/bin/sh
VBoxHeadless -s "Windows XP VM"

And run it from within screen (to keep the process alive after disconnect).  After that I just RDP into the box and use it like a home away from home.  Pretty handy, especially if you had a multitude of machines you wanted to bring up and use then shut down without having to first vnc/remote into another gui, then start the virtualbox gui, and use the gui from a gui gui gu gui… gui.