I tried running it from LiveUSB (PenDriveLinux) to USB, but found it was faster (in speed) going from Live CD to 16gb USB. I may go back for a 32gb USB, but I see people running Ubuntu on next to nothing.
As for the GUI. If you're referencing my situation, I'm not running Ubuntu Server, so I do have a GUI. From what I understand, 11.10 and higher will see the amount of RAM I have without a problem, so I really see no advantage to having server version.