I for one believe the planet at the end of halo 3 is reach. I can't think of any other reason Bungie would show that cut scene. BUT I think time travel isn't plausible, it's just not in Bungie's design style. So I was thinking what if Reach played out similar to ODST? You have the Chief wandering the ruins of Reach (not unlike the rookie). He finds clues to events that happened in the attack, you then play a level through the eyes of the 5 guys in the picture. I'm sorry if it's a crazy idea but what the hell there you go.
[Edited on 08.07.2009 10:57 AM PDT]
ok doont mean to ruin anyones ideas but why would MC need to wonder around reach after the battle? considering if its tied into the books MC went back to reach and already knows what happened so what would be thew point?
S