Games I'd recommend
Dragonball Z Budokai Tenkaichi 3. A great action packed game that really puts you in the action and experience. the Wii motion controls were MADE for things like Dragonball Z. IGN E3 2008 winner of Best Wii Fighter.
Naruto Shippuden: Clash of Ninja Revolution 3. Don't let the Naruto skin fool you. Grab a calssic controller and you'll find a suprisingly deep fighting game, with cool special attacks and very different characters.
Arc Rise Fantasia: A fun JRPG with the sad drawback of atrocious voice acting. Get used to, or just mute them, and you'll find this is a great RPG with great weapon customization, with a unique magic system.
Onechanbara: Bikini Zombie Slayers. This game not only lives up to it's title, but is an amazingly fun hack n slash that uses the Wii's motion controls really well. This game is very under appreciated, sadly.
Tatsunoko vs Capcom: An AMAZING fighting game, and the latest in the VS Series. Anime powerhouse Tatsunoko (who made anime such as Gatchaman, Karas, and Tekkaman Blade) vs Capcom, bringin in characters such as Megaman Volnutt, Frank West, and Ryu. Can't recommend this game highly enough.
Tales of Symphonia: Dawn of the New World. Gets a ton of hate for reasons I'll never understand. Continues the story of the Gamecube mega-hit, and adds in 2 new characters with a very well told romance. Improves the gameplay in almost every way from the original, and adds in the ability to capture monsters you fight and have them fight with you. Great RPG.
Games other people have recommended that I also recommend:
Madworld
No More Heroes
No More Heroes 2: Desperate Struggle
Fire Emblem: Radiant Dawn