Edit: Ach! Necrobump! Sorry guys. Bungie has never done "f bombs" in any of their games. I don't think they're necessary. I'd prefer a Firefly-esque system of swearing. As far as violence goes, so far we've got very little blood and lots of guns that incinerate. That being said, I still think it'll be rated M for marketing reasons. Just like the Halo games were. (Yes, I know the ESRB isn't connected at all to the companies... in theory.)