i'm definitively done with WoW, but i remember having a good time with the classless private server Ascension. The gimmick is that you put together a build of not just talents, but spells too, so you could be an archer that uses frost effects instead of snares and a pet, or a sword and shield combatant that uses shadow magic. I think they're on the TBC expansion, but using a Wotlk client atm, which means it takes up very little harddrive space.