Well it'd help if you said what you like. If you don't like racing games, Mario Kart wouldn't really be a very good recommendation, would it? The Wii games I've been playing most recently are One Piece - Unlimited Cruise, Twilight Princess, Mario Kart and Dragon Quest Swords. Bearing in mind that I'm a fan of the DQ series and of One Piece, so those games might not appeal to you at all, though I do think they're both good in their own right.
Another great game is Muramasa. It's a side-scrolling beat 'em up that plays sort of like a cross between Streets of Rage and Devil May Cry and looks sort of like a 2D Okami. Oh, and there's another great game on the Wii: Okami.