I really liked Super Mario Sunshine, so I couldn't wait for the next Mario console game.
Instead of a water-gun/jetpack and a tropical island, Mario was sent out to space. I really liked the little planets, and how they could diversify the game with many different kinds of areas.
I really liked the new power-ups too. Bee Mario was awesome.
The last boss fight against Bowser was pretty epic too. Along with the other bosses in the game.