Red Dead Redemption. To the surprise of the few that hijacked an early copy, the PS3 version includes exclusive content, marked by a special sticker pasted on the box. According to the packaging, it includes "PlayStation 3 exclusive content" like "Solomon's Folly Gang Hideout" and the "Walton Gang Outfit." There is no sticker on the Xbox 360 version.
We're surprised neither Rockstar Games nor Sony have yet to announce this potentially platform-deciding detail; thankfully, there's still time to change your pre-order, for those of you that absolutely need to ride around the Wild West wearing a top hat. Assuming, of course, you haven't already purchased the game from your local street date-breaking store.