1: Pokemon Diamond.
Simply because I've spent over 800 hours on it, and it's the only game I've played for more than 200 hours. There shouldn't be much to discuss there.
2: Super Mario Galaxy 2
Amazing game, amazing soundtrack, amazing everything. Probably is the most perfect game I've ever played. I can't come up with one thing that the game did in a bad way. It's also the main reason as to why I bought number 4 on the list, since it made me listen to video game music.
3: Endless Ocean 2
A really obscure game. But it's an fantastic one. There were so much to do, and almost every part of it was relaxing, and the parts that weren't were usually good in some other way. The game deserves more cred than it gets.
4: Xenoblade Chronicles.
The revival of the old Final Fantasy. Good art style, fantastic soundtrack, amazing world and the best story in any video game I've played.
5: Mario Kart Wii
I feel it's kind of wrong to put this game so high up on the list, since it's far from perfect in any way. However, the amount of fun I've had with the game makes up for it. We have yet to invent a game that is better for parties than this one.
6: Skyrim
7: Skyward Sword
8: Twilight Princess
9: Super Mario Galaxy
10: Metroid Prime Triology.