Castlevania on PSP or DS is my bet. I'm actually expecting a port of Symphony of the Night on one of those systems (most likely PSP)
however, the 2d castlevania's have gotten a little stale, but perhaps that was just because of the 3 in 3 years issue, i wouldn't mind another one. Circle of the Moon is my fave out of the GBA 3, (aria being second, i hated harmony) and it seems that lament wasn't as good as it needed to be... I'm really curious to see what the next castlevania will be.
I would love some sort of 2d game with a 3d map, like if you see a door in the background, you could go into it, and then it would have crazy intersecitng passages and everything.
seems like a damn good idea that could be implemented with enough ingenious thought... and seems far more suited for castlevania than metroid in my mind.