Almost like every game is compatible with Vista. I'm running Vista Ultimate 64bit, and Have downloaded a LOT of mmo's , all of which worked.
And whenever you come across 1 that perhaps crashes your system, just right click on the .exe >> go to properties >> compatibility tab>> Check off run in compatibility mode >> choose XP SP2 in Drop down menu
and sometimes you might come across probably an anti-hack shield like nprotect that might not work. Do some research and change the IP in your windows HOST file to an alternate one compatible with vista (your going to need to find these IP's on your own tho. Most likely from forums)