Well, we should all remember that the next main KH is not going to be named KHIII, and maybe that game will be the same as what you guys call Knight's story. I mean, KH sequel and KH Knight's story are only one game, maybe. If that's true, I'd like it for the Wii.
If they're different games, I mean, there's a KHII sequel and a KH Knight's story, I'd like the main sequel to be on the Wii, and the spin-off for multiplatform, PS3/Xbox360. That way Square-Enix would show great support for both Sony and Microsoft. Think about it.
On the subject of multiplatform, where KH, FF and Tales of go, that's where I'm going. I already have a Wii, but it's a given that I'll have a PS3 and/or (more possibly or) in the future. Where most interesting RPGs plus other awesome games go, I'll go too. PS3, I'm looking at you.