PSM3, in their rumours section, have reported that Bungie's next game won't be here in time for this generation of consoles and will instead be released for the next generation consoles. What this says about those console's release dates is difficult to pin down, but there have been rumours of a 2013 release for whatever Bungie are working on and, if this is a launch title, late 2013 is probably a decent guess.
The rumour also says that the new game will use the same engine as Halo Reach, so if you enjoyed that game you'll probably be quite impressed with whatever is coming. That doesn't necessarily mean the game will be little more than a graphical update and reskin, the engine will have been massively modified so suit whatever it is they're working on. Bungie's next game will be published by Activision, the IP is owned by Bungie (unlike Halo).
Of course, this IS just a rumour and smart bets are on this being at least somewhat wrong. Watch this space.