I got my Wii a year ago, and up to date, I have only found three games that were good: Wario Ware, Super Paper Mario and Mario Kart. I found Twilight Princess too dungeon-based, and the plot was very confusing for me -_-; Mario Galaxy was... too overrated. I even prefered Sunshine's difficulty level better. And I still have to start Brawl's adventure mode -.-
Mario Kart is very good. It's the first Nintendo game where the Online is more important than the 1-player mode. And the motorbikes are a great addition. The wheel is ok, but I prefer my remote better XD.