Depends on what kind of games you like. There are the standard Mario games (Mario Kart, Super Mario 3D Land, New Super Mario Bros. 2) if you like those.
Monster Hunter 3 Ultimate is a great RPG. A bit of a learning curve, but still fun. I've heard good thing about Tales of the Abyss, and Kid Icarus: Uprising is a great game with very nice graphics and music. Fire Emblem is a good strategy game, but it can be tough at times (from what I hear).