Quote Originally Posted by 'OogaJiggaWooga',index.php?page=Thread&postID=1729 96#post172996
I run one of my slaves from my WD 60GB usb drive. It's a small form factor hard drive and not a usb key, but I have had no problems whatsoever running WoW from this (I also took it in to Uni a few times to make the tedium a little more bearable).
An external usb HD is fine of course.