I think they already said something about a Wii Zelda (TP was a GC port, wasn't it?).
A second "Wii Play" game. (for the zapper)
I would guess a Wii Sports 2 will come some day (using Balance Board + Wii mode?). Another Mario Party will come for sure. And well, maybe a Donkey Kong game.
But your right, i also thought about how Nintendo is bringing all the big guns out till early 08. They seem to be confident to keep up with demand at some point. What big franchise Nintendo has left for the Wii, all the Big seem to come in a little over 1 Year. Nintendo has to fill 5. So i think, they have plans they don't talk about at the moment.
Join up to the VGC Mario Kart Wii GP European League!
Or the VGC Mario Kart Wii GP Australian League!
Or the VGC Mario Kart Wii GP American League!
Or the VGC Halo 3 American League!
Or the VGC Call Of Duty PS3 League!