I'm late but I gotta say I read some great recommendations. If I had to name my favourite Wii games I would name:

• Donkey Kong Country Returns
• New Super Mario Bros Wii
• Punch Out!!
• Fire Emblem: Radiant Dawn
• Super Mario Galaxy 2
• Resident Evil Remake (that if you ever played the original and never the remake)

Those games are so good that there is no I'm a HD whore excuse to them.

Sin And Punishment 2

Dragon Ball: Revenge Of King Picollo

Endless Ocean 2

Monster Hunter Tri

Kirby's Epic Yarn

Fragile Dreams

Final Fantasy Fables: Chocobo's Dungeon

...and if you're having a party Just Dance 1 and 2 are insane.

Wait for Xenoblade. God tier game.

Silent Hill: Shattered Memories

Twillight Princess, if you like zelda games

Get GTi Club: Supermini Festa! if you like arcade racers that you can enjoy with friends.

Don't take any notice of the reviews, as they just compare the game to the PSN release, and pretty much penalise it for not being in HD (despite having tons of extra content).

Zelda...smash bros...and yep that's it have fun, the wii's library is, "GREAT"

Paper Mario for the N64 (VC) and GC (disc).

• Listen to D21lewis. His list is good. No matter what you get, the Mario Galaxy games are a must.
•  Metroid Prime 3(or trilogy) and Red Steel 2 are among the best hardcore motion experiences ever.
• I personally like No More Heroes but the gameplay is average, tbh. The character and boss battles are so sweet, in fact, it should just have been watched as an anime and not played.
• If you had to have only 1 game, then it's Smash Bros Brawl. That it my best multiplayer experience of all time.
•  I personally like Dragonball Z:Budokai Tenkaichi 3 but you might not be into anime based third person fighting games.
• You might as well get Mario Kart and Wii Sports resort since there are hardly any HD games like them and you might want to go for wii experiences that are hard 2 find on your HD console.
• The Legend of Zelda:Skyward Sword, releasing later this year. Even if it is not as good as previous Zeldas, i can't see it ending up too bad. I personally hope it will be the best adventure game of this gen(fingers crossed).
• If you've never played a Zelda game(or have played only the 2D ones), get Twilight Princess also. It's biggest problem was that it re-used the same zelda formulas that had already been overused before, but you can't detect that if you haven't played any of the 3D zeldas.

Evidentally you could do yourself a favour and read either Smeags' thread or previous comments in this one

I heard that Eternal Darkness, Sanity's Requiem is the most underrated gamecube game. I've never played it. But if you're gonna be getting gamecube games and you like the character 'Link' from the legend of zelda series, you might want to get Soul Calibur 2 as Link is a character there.