Best Mario game of all time period - Super Mario Bros. 3. It's seriously the best game ever made, in my opinion.

If you want to split it between 2D and 3d:

Best 2D Mario - SMB3

Best 3D Mario - Galaxy 1. If they did an HD remake of Mario 64 (yes please), that might take the cake.

Mario 3 and Mario Galaxy 2 are the best.

I'd normally say Super Mario 3 or Super Mario World and be 100% confident in my answer. Thing is, I just bought Mario World for the Wii U and I'm not having the fun I used to have on SNES and GBA. I also got that Super Mario Anniversary thingy with Mario 1-3 and Lost levels. Didn't finish a single one.

So, as it stands, I gotta go with Galaxy with 3D Land as the runner up.

Galaxy and 3 they both blow me away

Super Mario 64, Super Mario Bros. 3, and Super Mario Galaxy 1 are my favorites.

SMG2 was good too, but SMG1 had some more "epic" levels so I give it the nod there (like that floating water tower fortress .... awesome).

Galaxy games and Super Mario World. Galaxy though was just unreal, MAGIC!

Super Mario Galaxy 2 is hands down the best !
64 and the original SMB were more innovative when they were released but Galaxy 2 is my Game of the Generation !

"Super Mario 64" is the best one for me. "Super Mario Sunshine" is very close to that number one spot.

The original Super Mario Bros. on NES is the one I had the most fun with, so that one.

Donkey Kong arcade