Final Fantasy XIII, but they got cut. An interview (in Japanese) over at FF-Reunion with art director Isamu Kamikokuryou ("No you!" to his friends) has him saying that the team removed enough extra locations from the title to make up a whole other game entirely.
Sections cut include a secret base for Snow's hero squad, a character's home that included a park, and even a zoo inside one of the game's amusement park areas. This is all more impressive when you consider that Square Enix is expecting to need three DVDs to hold everything that's still in the Xbox 360 version of the game. But FFXIII completists, don't worry too much -- we're sure some of that content will appear sometime during the game's 10-year cycle.