Hum, let me take a look at the shelf
Wii sports Resort (WM+ is awesome on this one)
Little king's Story (great mixture of RPG-Strategy and Adventure with a funny and sometimes hilarious history)
Boom blox 1 and/or 2 (simple and straight, but funny to play and with really enjoyable physics, the level editor is as much fun as the own game)
Tales of Symphonia (the classic Tales of RPG feeling with some new features that make it fresh)
Baroque (Dungeon Crawler with a dark and creepy ambient, a bit difficult but chanllenging and interesting to play)
FF Fables: Chocobo's Dungeon (despite it's childish aspect it a great Dungeon Crawler RPG)
Another Code R, Secret Files Tunguska/Puritas Cordis (Point and click adventures with quality and enought lenght)
Madworld, Spyborgs (if you like Beat em up games those two are a must have, I would recomend OneChambara too, but that's a much more personal choice)
Spectrobes Origins (if you've always dreamed with a PKMN 3D RPG on a home console that's the closer you'll get by now)
The munchables (platform game with a bit of RPG and all the weirdness and fun you can spect from a japanesse game)
Opoona (some kind of Social-RPG, so sepaking to the characters and completing lots of tasks is more important than equipment and leveling...)
Endless ocean (relaxing and amazingly beautifull, not really a game as is, but a great experience to play anyway)
RE: Umbrellas/Darkside Chronicles (Amazing onrail shooters with a different style and gameplay than Houses of the dead, lot's of unlockable content and replay value, especially funny for multiplayer)
Okami/ Zelda TP (if you like RPG-adventures those two are the best on the console, long lasting, epic and sometimes emotive even, will leave you a great taste after finish)
I'll edit the post to add more games, cause it's hard to select a list from my 75 games collection (which I mostly love every single one so....). If you like some specific genres would be easier.