I'm gonna take a page out of Combine's book, and post some upcoming games that are in the pipe for the Wii for the rest of the year. Some of these are must haves, some of them just look interesting.
But let's start with the grand-daddy.
new Super Mario Bros Wii

Take classic 2D Mario gameplay, the 3D graphics of nSMB and add in 4 player co-op/competitive action. It may not be the best looking game this year, but it seemed to have been one of the most fun at this e3.
Metroid Prime Trilogy

After the Orange Box, I think this is probably the most valued pack deal this generation. 50 bucks gets you 3 of the best games ever made. The first two have been upgraded to include slightly enhanced graphics as well as new control schemes and an achievement system to unlock art work and take pictures. It also includes an art book and a cool case. And its out next week.
Muramasa: The Demon Blade
A really nice looking game that seems to harken back to simpler times.
TMNT: Smash Up
I already have an on-going thread for this game. But take the awesomeness of the Ninja Turtles and the hectic chaos of the SMash Bros engine, and you have one hell of a fighter on your hands.
Dead Space Extraction
The Wii is in no way short on rail shooters, but this self describe "guided experience" is the prequel to one of the most frightening games on the 360/PS3. It also features co-op play and alternate routes to expand the replayability.
Silent Hill: Shattered Memories
A horror game with a twist, as it really makes you feel helpless with no combat. There is also the psychological profile that changes the appearance of characters and locations you visit. If you want a brief sample, check out this trailer and the one from e3 which are pretty much the same trailer with different options chosen.
Rabbids Go Home
The zany Rabbids from Rayman Raving Rabbids finally get a starring role in this Beautiful Katarmi-esque adventure game.
Tatsunoko vs. Capcom
The spiritual successor to the Marvel vs line of games. This time it sees the gang from Capcom taking on some of Japan's biggest anime icons.
There are still games that would impress but are across all three platforms like MUA 2, Shaun White and others.
Also I decided against posting Modern Warfare as I feel that is just a slap in the face. Its a 2 year old game that doesn't look half as good as the original and comes out same day as the much improved sequel.