I'd like to see Nights on the Xbox, solely because of how PDO looks on it. I'd say no to it being on the PS2, simply because (it seems) that large worlds can't be properly done.
All things considered though, it'd fit right in with GCN games. Which is why I WOULDN'T want it to be on the Cube, simply because it'd be passed on as 'another kiddie game'. For Nights to do well, it has to be perceived as a fun game that transcends age. The Cube has a very tragic stereotype that keeps people away from games like Pikmin.
I read of rumours that SOR 4 would be on the Xbox. But again, just rumours. I really wish that Sega didn't make that stupid RE clone, Zombie Revenge for the DC. The game could have been so incredibly amazing, if they dropped the RE theme and stuck with the classic SOR and added some of the music the franchise is famous for (a remixed SOR2 - level 1 track would have been awesome). What I'd like to see is Adam, Axel, Skate, Max, Blaze (Dr. Zan was a stupid idea) in a four player brawler.
Afterburner is definetly a made for PC game. People nowadays don't seem to be interested in console flight sims.
Burning Rangers, well that game is cool, and would be an excellent title for the GC, only if they fix that stupid nav system. Same goes for Shining Force, although I'd like it to be multiplatform, just so it can some thunder away from the FF series.
I see Gunstar/Guardian Heroes on the GC or Xbox, not the PS2, mostly the GC. I have no thoughts on Vectorman or Comix Zone, although Comix Zone had a really good idea going.
The PS2, at least to me, is the antithesis of Sega, just in terms of the type of games and the kind of people that play the PS2, so it's hard to imagine people enjoying games like Sonic on it. But again, it's just me.