Okami!

Okami Amerasu, mother of us all...
This and Final Fantasy III are probably my two favorite games of 2006, not including the general excitement of actually having a Wii.

I actually finished this as well - almost 100 hours of gameplay overall, with trying to get various side-quests done on top of the main storyline.

You get to play as a wolf-god, who can use brush powers to actually change the environment of the game - for example, hit a shoulder button, and slash the screen with the analog stick, and you've cut a fruit down from a tree (or killed an enemy, or split open a rock...)

Beautiful cell-shaded artwork as if you are running around inside a Japanese watercolor.
And it's just plain fun to play. Not too hard, and not really too easy either (at least for me). I just love this game.