Goombanator said:
Wasnt Halo the other way around? Bungie started as part of microsoft studios then became a third party.
Bungie started as a Mac developer (See: Marathon), Microsoft bought them during the production of the first Halo (which was, at various times, an RTS, a 3rd person action RTS, and finally an FPS), and then spun them out as a seperate developer but held on to the Halo license.
There's no reason now that Bungie couldn't produce multiplatform games, (they actually did make one PS2 game, Oni), but I suspect they'll stay tight with Microsoft, mates rates and all that.