Air Rivals is pretty fun - once you hit Level 22 (a week or so of moderate grind) you can go anywhere and take part in the whole PvP war that goes on.
Oh, and it's basically Freelancer the MMO. Instead of walking up and hitting 1,1,1,2,1,3, you fly a fighter, or bomber, or siege craft, or support craft, and blow the shit out of shit.