In terms of unannounced games/surprises...
Realistically:
DS - New Super Mario Bros 2
DS - new 2D Metroid
DS redesign to be launched by the end of the year
Wii - Mega Man 9
Wii - Animal Crossing
Wii - Mario Party 27 with Balance Board support
Wii - Kid Icarus trailer, out next year
Wii - The Legend of Zelda trailer, out next year or later
Wii - brand new 2D Castlevania that links up to Order of Ecclesia
In a perfect world:
DS - Golden Sun 3
DS - Metal Gear... to prove that Nintendo didn't just advertise a PS3 exclusive in their own game...
DS - Mother 3
Wii - whatever Monolith Soft is making besides Disaster: Days of Crisis
Wii - Metal Gear... because Nintendo deserves 2 original Metal Gear titles for putting Snake in Brawl
Wii - a RE4:WE style Resident Evil title
Wii - Eternal Darkness 2
Wii - Starcraft Ghost... yeah, I know....
DS/Wii - some original IPs for Nintendo and 3rd parties