I second Skyrim. I suggest Borderlands/Borderlands 2, especially if you can play with other people (you can match with randoms but they are nubs and trolls). Also, I've been playing SW:TOR which seems to be pretty fun. I've heard great things about Guild Wars 2. I've had more than one person tell me it was the best leveling experience they had ever had in a game, and it starts to suck at endgame.