Yeah Mario 64 was one of the N64's shining games for sure. It's only problem was quirky camera issues that plagued all 3D games for years, although it's far from the worst of the lot. And of course sub-par 3D graphics compared to later releases, although that's not really a fair criticism I suppose.
Although, I personally think Super Mario Galaxy blows M64 out of the water as the pinnacle of 3D Mario gaming although M64 is a close second.
Best 2D Mario platformer: Super Mario World (SMB4)
Runner-up: Super Mario Bros. 2
Best 3D Mario platformer: Super Mario Galaxy
Runner-up: Mario 64