New Super Mario Brothers, whether that be 1 or 2. Odyssey is more amazing but all that 3D playing can make me feel car sick, and getting lost all of the time / retracing previous steps you made gets old.

Super Mario Bros 3

Galaxy is one that I've played enough to actually have an opinion about, so probably that (though I feel like Party is great too)

I'm a broken record, but its by far Paper Mario and the Thousand Year Door.

I think either SMB3 or Marie 64.

2D platformer: SMB3

3D platformer: Galaxy or Odyssey

Spin-off: Paper Mario: The Thousand-Year Door

It's either one of the Super Smash Bros or the Luigi dating sim I'm making that Nintendo will be suing me over soon...what do they know of love anyway?

Super Mario 64 DS