GameFly seems to have let loose the official word on the Microsoft Xbox 360 release of Final Fantasy XIII. Their rental page for the upcoming Square Enix game points out that
NOTE: This is a three disc game, but it only counts as one disc against your rental plan.
In Japan, this game is only available for the Sony PlayStation 3, and takes advantage of the expanded storage that Blu-Ray offers. The amount of discs for the game, on the Xbox 360, was unknown up to this point.
Personally, I think the Final Fantasy franchises took a turn for the worst with VII. There’s no doubt that the early iterations had some great gameplay, but once Square realized they can pad it out with CG story and spread it out over multiple discs with VII, they went lazy with the gameplay. One of the recent Final Fantasies would effectively play the game itself. I’m still waiting on The Spirits Within to be released as a full-on entry in to the Final Fantasy franchise at this point (chapter skips unlock achievements?).