
In a meeting with Hiroshi Ogawa, Director for Infinite Undiscovery, and Hajime Kojima, Producer for the title, IGN learned for a second time at TGS this year that a game coming to Xbox 360 would require multiple discs. This time around, it's Infinite Undiscovery.
IGN says to get used to the notion of a multiple disc games on Xbox 360. It's looking like you'll be seeing a lot of it in the future.