Wii
1. Super Mario Galaxy
2. No More Heroes
3. Zack and Wiki
4. Super Smash Bros. Brawl
5. Metroid Prime 3
Lets see - Arguably the greatest platformer ever made, the goriest (the US version, at least) and arguably most stylish beat em'up ever made, a tough family-friendy puzzle game, an excellent multiplayer fighter that can be enjoyed in a variety of ways, and a somewhat different take on the FPS genre.
For some variety - a list completely void of first-party games:
1. No More Heroes
2. Resident Evil 4
3. Zack and Wiki
4. Boom Blox
5. Tales of Symphonia: Dawn of the New world
I had to keep NMH and Z&W on the list since they're such awesome games. Plus, Resident Evil 4 is a multiplat game, but the Wii version is superior to previous iterations, so it deserves its spot IMO.
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