Sequels to basically any previously released games would be welcome. Metroid is the obvious choice for a new game. I would kill for a handheld Pikmin. Then there's always the surprises that we just haven't thought of. I don't think a lot of people saw Kid Icarus or Luigi's Mansion coming, so I'm hopeful that they've still got some tricks up their sleeves.
Currently playing:
Bloodbath Paddy Wagon Ultra 9