Twilight Princess.

If that wouldn’t count either due to being a Gamecube game originally then Mario Kart Wii.

One of my most-played games on the Wii was a launch title, and it doesn't have Zelda: Excite Trucks. I'm still bummed that the successor never came to Europe...

Other than that, I played a lot of Smash (when it worked, most of the time it wouldn't read the disc properly), House of the Dead: Overkill, No More Heroes and MadWorld. The latter 3 especially with my German friends, as they hadn't access to House of the Dead or MadWorld due to their rating from the BPjM.

But apart from all those, my favorite Wii game is probably a bit controversial. It's actually Fire Emblem: Radiant Dawn and my favorite Fire Emblem game period. It's story about how hellish War is, how ambition can be corrupting and all it's other themes that are completely absent from modern Fire Emblem games still bring me back to this title.

Oh, and as for my favorite WiiWare game, it's Final Fantasy Chrystal Chronicles: My Life as a King, followed by Megaman 10 and World of Goo.

The best version of the best game Resident Evil 4.
Ah, how I miss the Wii motion controls for this game. Sure it made the game a bit easy, but it was just so darn fun.
The tank controls is a bit frustrating when I revisit the HD versions, tank controls + pointer motion controls is a good middle ground.

Skyward Sword is 'til this day the first playthrough of any game that I enjoyed the most. But I have only ever played it one time, it is almost like I am afraid to revisit the title and tear down my view of the game.

When looking back at the Wii era I played The Galaxy games, Zelda TP, Zelda Skyward Sword, Wii sports and Resident Evil 4. that's pretty much it. Maybe a few virtual console titles as well. I played the GameCube version of both Mario Kart and Smash since I prefer them massively to the Wii counterparts.

Sin and Punishment 2.

Okami
Xenoblade Chronicles
Skyward Sword
Metroid Prime 3
Super Smash Bros Brawl
Little King's Story
Muramasa the Demon Blade

DKCR needs a little nod here

I love this thread because I love the picks of pretty much everyone. The Wii was truly a special console...

To say something different, I LOVE Wario Land: The Shake Dimension. Best Wario Land game ever and one of the most beautiful games on the Wii, both visually and in its music. Besides that... It was just good fun!

Goldeneye 007 Remake was awesome too. I'm not much of an online guy, but I poured hundreds of hours into this. I was playing it sporadically as late as 2017-18. Sadly the servers went down...

And of course, Metroid Prime 3: Corruption. My favourite of the trilogy. I know, it's not a very popular take... But I just loved the slightly more action focus and traveling to different planets while keeping good old backtracking and puzzle solving for upgrades.

I'd choose Twilight Princess but since that was a Game Cube fame I'll choose Wii Sports cause of the Golf. Never was there such a fun golf game (Everybodys gold VR is better but very limited and solitary). Many hundreds of hours played with friends on local co-op on the golf alone but the other games make Wii Sports just amazing, it was like California games on the NES and everyone wanted to play it if asked, just pure fun and friendly competition.

Hopefully if VR ever gets its wii moment and a device that makes it become as easy as putting on sun glasses and donning some gloves at prices as low as the Wii or Switch, we will see games like that again. Meta Quest has a chance but they are updating devices to soon for any real breakthrough where one device becomes the staple for casuals at home. It would take a new device, by perhaps Nintendo, to make that a reality cause VR is so damn impressive and really has the capability to compete with TV's, laptops and phones for the share of eyeballs.

Donkey Kong Country Returns. Masterpiece!

Besides Mario Galaxy 2 that's one of my favorite game ever, I think Zelda Twilight Princess is a great choice, but I have some really good experience with other games on the Wii that I'll put the names below:

The Legend of Zelda: Skyward Sword

Rhythm Heaven Fever

Super Smash Bros Brawl

Tatsunoko x Capcom

Madworld

WarioWare: Smooth Moves

Xenoblade Chronicles

The Last Story

Sins Y Punishment Y Fold: Star Sucessor

Pandora's Tower

Fire Emblem: Radiant Dawn

Rune Factory Frontier

Harvest Moon: Animal Parade

Sakura Wars: So Long My Love

Final Fantasy IV: The After Years

Final Fantasy Crystal Chronicles: My Life as a King