Super Mario 64 obviously was the first 3D and as such pretty mind-blowing at the time. But I do remember not liking the control and gameplay near as much as older 2D titles. Galaxy was also incredibly innovative, with outstanding presentation and better control and gameplay than 64. The whole theme of that game was amazing.
But my favorite is actually SM3DW, which I'm playing now. I can't stop playing it actually. I love the modern 3D presentation and production values mixed with older 2D gameplay, control and powerups. It is simply an amazing, addictive, fun, innovative game. Every level is a new puzzle or experience and there is so much gameplay content... I love it.
The only area 3DW comes up (relatively) short is on innovation and theme/style. If you took an innovative style or idea like Galaxy and gave it the gameplay of 3D world it would be perfection. 3D World also needs a better name... but it's a near-perfect execution of Mario gameplay.
