Wii Recommendations

[Scull]

In the vein of the PS3 recommendations, here is a centralized place to put Wii recommendations. List the game, note if it is a buy/rent/or other special circumstances.

[Scull]

Disc:
Boom Blox (buy it)
De Blob (buy it)
Warioland Shake It (buy it)
Super Mario Galaxy (buy it)
Metroid Prime 3 (rent it first, it might not be your thing)
No More Heroes (rent it first, it might not be your thing)
Ghost Squad (rental, rail shooter, but a ton of fun with a big group)

[zarathstra]

Fire Emblem (if you like Tactical RPG's)
Super Smash Bros. (if you like that series)

[Iron Past]

I'd say Resident Evil 4, if you never played it. I finally got around to finishing it yesterday, and it's pretty fun once you get used to the controls.

[Ravenlock]

Disc:
Boom Blox (buy it)
De Blob (buy it)
Warioland Shake It (buy it)
Super Mario Galaxy (buy it)
Metroid Prime 3 (rent it first, it might not be your thing)
No More Heroes (rent it first, it might not be your thing)
Ghost Squad (rental, rail shooter, but a ton of fun with a big group)

Fire Emblem (if you like Tactical RPG's)
Super Smash Bros. (if you like that series)

In addition to Scull's choices and zarathstra's, which were good:

On Disc:
Battalion Wars II (rent first, try it out)
SSX Blur if you don't have the balance board, Shawn White's Snowboarding: Road Trip if you do (rent it if you don't like SSX-type games enough to buy)
Dokapon Kingdom (buy it, it's hilariously fun with friends and cheap at $20)
Zack and Wiki (buy it)
Okami, especially if you didn't play it on the PS2 (buy it)
Godfather: Blackhand Edition (I'd say buy it, the motion controls make it much better than the versions on the other consoles)
Any of the Lego games, especially if you have kids who play (rent/buy depending on how much you like unlockables)
Twilight Princess (buy it)
Excite Truck (buy it)
Mario Kart (buy it)
Star Wars: The Force Unleashed (rent it and cheat - it's actually pretty good that way, and the story is worth playing through)
Williams Pinball Collection (buy it - very accurate, fun recreations of lots of classic tables, and it's also cheap, <$20)

Strongly second the recommendations for Smash Brothers, Boom Blox and especially de Blob. Those are all awesome as well.

On WiiWare (obviously to buy, as you can't rent):
Lost Winds
World of Goo
Tetris Party
EDIT: Forgot MM9 :o

Virtual Console would take too long to list, it's full of awesome.

[Stoke]

I have to put in a vote for No More Heroes. I still miss it even after 4 months with no Wii.

[Variable Gear]

Disc:
Geometry Wars: Galaxies (buy)
No More Heroes (buy)
Boom Blox (buy)
de Blob (buy)
Wario Land: Shake It (buy)
Zack and Wiki (buy)

WiiWare:
World of Goo (buy)
Lost Winds (buy)
Helix (buy)
Mega Man 9 (buy)

[BLeeP]

Super Paper Mario (BUY IT!!!)
Chocobo's Dungeon (Rent to try, or buy if you know you like dungeon crawlers)
Animal Crossing (Buy, unless you are, for some reason, bored with the idea)


WiiWare
Final Fantasy Crystal Chronicles: My Life as a King (Everyone needs this)

[Urizen]

To stray from the beaten path here, I'll give a nod to Tales of Symphonia 2 as a must for anyone who played the original. NMH is my favorite release of 2008.

Trauma Center: New Blood is an excellent but very difficult co-op title. RE:Umbrella Chronicles is a great mashup of light gun games and RE.

VC's best include DKC2, Sin and Punishment, Super Metroid, StarFox 64 and Super Mario RPG.

It's going to require finding an NTSC workaround for region locks, but Tatsunoko V Capcom is the best traditional 2D fighter since MvC2. I know I'm going to end up dropping hundreds of hours into that one.