You're buying it again on the PlayStation 3? Just for that forgettable exclusive content that doesn't even really fit in with the game to begin with? And you realise that these days there's rarely such a thing as a full exclusive anymore, and that it'll probably make its way to other platforms eventually, right?
Well, if that's worth $70 to you, then that's your prerogative. But I can tell you that the Xbox 360 is not the place to find really immersive games. BioShock is almost a fluke that way. :P