Oh boy, this is really hard. Pretty much all exclusives could go in on the list. But the game that made me go "Wow, what I'm playing is so beautiful that I wouldn't mind dying right now" was Super Mario 3D World.
Music: Masterpiece. Gameplay: 100% fun. Story: Simple and yet interesting. Simplicity works. Level Design: Perfect. Just perfect. Graphics: So smooth.
Oh, and the game is only 1.7gb. So you don't have to wait 4 hours to download/play a 30+ gb game with updates and stuff. What the people on Nintendo do with their franchises is just unbelievable.
Normally I would say Super Smash Bros. or Mario Kart 8, but Pokken Tournament is quickly becoming one of my favorite all time games. I'm not really sure what my favorite Wii U game is right now. :\
“The media's the most powerful entity on earth. They have the power to make the innocent guilty and to make the guilty innocent, and that's power. Because they control the minds of the masses.” - Malcolm X