Mad World. Even if that was the ONLY worthwile future release for the Wii, it would be more than enough.
The Wii is getting a Wiiware release of Cave Story. That is also quite awesome.
As for future nonwiiware releases that I am looking for:
Dead Rising: Chop til you Drop. Why? Because I lack the 360, and if it is half as fun as the Wii version of RE4 (which is THE superior version, due to pointer functionality), it'll be a blast. Hopefully, Capcom will decide to do a downgrade/upgrade like that for RE5, or port it to the Wii's succesor, because as long as RE5 is not in a console with pointer functionality, it'll be inferior to RE4.
Punch Out Wii is OBVIOUSLY something that I will get and love. Loses points if it does not have Soda Popinsky/Vodka Drunkensky, though.
As a Treasure semi-fanboy, I can't be anything but excited at the prospect of being able to play Sin and Punishment 2.
SSHIT, Sin and Punishment 1 is awesome, even if it feels a bit clunky with the GCN controller. The Wii sequel will have pointer functionality and it'll be incredible. Mark my words.
House of the Dead: Overkill.
It is fucking House of the Dead. It is going to be great and you know it.
The cheesy trailer is the best thing.
Muramasa: The Demon Blade, by Vanillaware is going to be gorgeous. I want to try it. Hopefully, they'll do all regions well, instead of just optimizing the Euro release, as they did for Odin Sphere. Seriously, having the prettiest slideshow in the world where your input is delayed by like a minute (or more) ain't fun.
Personally, I want to get (and play) Wii Sports resort. Wii Sports (and to a lesser degree, Wii Play) are damn fun when people come over. With or without alcohol being involved.
i rented De Blob, and am interested in acquiring a copy for myself. It is a pretty damn interesting game. I am also interested on Wii Music, should be fun for at least a while, and if not, at least my mom will be somewhat interested on it.