Like DL said, I'm sure someone will come along and provide an exhaustive list... but Super Mario RPG, Super Mario 64 and Super Mario Galaxy (as well as its sequel) are all terrific games by anyone's standards. Also, if you want a GBA title, Mario & Luigi: Superstar Saga is worth picking up. Emulate it if nothing else. The dialogue and characterizations alone make it worthwhile, but the gameplay is also solid.