A few of my favourites:
-New Super Mario Brothers Wii (especially good for Co-op)
-Blast Works (quirky shooter with some cool ideas, such as collecting destroyed enemies as attachments to your ship)
-Monster Hunter Tri (awesome online RPG experience - good if you liked PSO. Bit of a learning curve but well worth it)
-Excite Truck (awesome fun racing game that it little silly and very arcade)
-Resident Evil 4 (In my opinion the definitive version of one of my all time favourite games)
-Okami (another port of an incredible game. If you like Zelda you'd probably like this too, but it's not the same game or even a rip off in any way as many people like to say)
-Rune Factory Frontier (great RPG/dungeon crawler/sim game)
-Super Paper Mario (fun game with an awesome sense of humour. One of the only games of the last decade to genuinely make me laugh my ass off in places)
-Wario Ware: Smooth Moves (if you haven't played this, you have to. It's awesome fun, especially with a group of drunken friends!)