XP is the best option.
There is absolutely no advantage to running Linux.
And just to get it out right away, I use Vista, XP, OSX, and various linux distros, so dont be ignoring me because of a microsoft fanboy status.
Running Linux, Vista, or OSX is just for show. XP is the most supported right now. And the purpose of a frontend is to mask the OS. So you wont even know what it is running. So choose a frontend whether it be Centrafuse, RoadRunner, StreetDeck, FrontRow (not sure of its name, it is the mac one), or some of the linux ones. See which one you like, and put the OS that supports that frontend. For GPS and everything, there is no question that windows platform is the winner. There is nothing even close on other OS's period.