Super Mario 3D World
Mario Kart 8
Nintendo Land
Pikmin 3
New Super Mario Bros. U
Bayonetta
Bayonetta 2
Super Smash Bros.
Pokken Tournament
The Legend of Zelda: Wind Waker HD
Xenoblade Chronicles X
Splatoon
Donkey Kong Country: Tropical Freeze
The Wonderful 101
Super Mario Maker
Honorable mentions:
Yoshi's Wooly World
Kirby and the Rainbow Curse
Wii Sports Club (What a GEM! Baseball + Golf with the gamepad are two of the coolest things on the system)
Mario Kart 8! I thought Super Smash was really underwhelming but lots of people love it. Splatoon is amazing too, and Mario Party 10 is pretty entertaining but only if you play it with friends.