That's NSMBWii. Easily. That was the first Mario game I got, but nostalgia is just a part of why I love it so much. In truth, as frustrating as it is to play it with your younger siblings, it still is a blast.
I love me some Mario Galaxy. I think I prefer the gameplay of Odyssey more, but Galaxy has it beat in every other way for me. I just love the story, the atmosphere (or lack thereof), the music, the characters, etc... Just everything. It's not my personal favorite Mario game. That title belongs to Bowser's Inside Story. Out of the main series, though, it's definitely at the top of my list.
Hello. I gave some better thought to this, and came to the conclusion, that I cannot compare games of different consoles. So I have to give a favorite Mario to each console.
If we're talking strictly platformers
NES: Super Mario Bros. 3 - it the closest NES Mario to being visually appealing to me, I find 8bit Mario uninteresting
SNES: Super Mario World - the cape ability really needs to comeback, it's so versatile!
N64: Yoshi Story- i like that it's designed to explore, and that it brings out Yoshi's potential
Gamecube: Super Mario Sunshine- Swoosh! Zoom! Splash!. I love zipping around with F.L.U.D.D.
Wii: Mario Galaxy 1 & 2 tied - It's like 64/Sunshine but with better physics and courses
Wii U: Super Mario 3D World - probably will be my favorite Mario game of all time the day I get to play it
Switch: Odyssey - kinda a given isn't it?
GB: Donkey Kong GB - they turned the arcade game into a whole side-scrolling adventure
GBC: Super Mario Bros. Deluxe - that Toad lounge, racing boo, and finding yoshi eggs were good additions
GBA: Super Mario Advance 2 - improved version of SMW, I hear it even had new levels through trading cards
DS: Super Mario 64 DS - SM64 redeemed: graphics smoothed out, can play as Yoshi Luigi and Wario, and a multiplayer mode
3DS: Super Mario 3D Land - its the only 3DS Mario platformer I've played so far, my opinion might change later