Though they said earlier this week that they'd be working on Halo 3 content for "probably" two more years, what Bungie really meant to say is that they were lying. Halo 3 ODST is definitively the end for Bungie and Halo 3.
"Halo 3 took two and a half years to make, and we're still working on it," Bungie producer Allen Murray said earlier this week at GDC 2009. "We'll probably be working on it for two more years."
When developers say things like that, even if it's not what they meant, we literal-minded gamers tend to take them their word for it. "Two more years" might have been hyperbole, a bit of exasperated "we've been working on this foreeeever" talk from Murray, but, for Halo fans who have heard time and time again that their favorite studio wouldn't be working on their favorite game after the release of Halo 3 ODST, it was a ray of hope.
False hope, apparently. "We'll never say never, but currently Bungie has no plans to make new Halo 3 content beyond the release of ODST," the studio told Eurogamer. "We will, however, continue to support the Halo 3 online experience with regular updates to matchmaking playlists and wield the Banhammer as needed." So, in terms of Bungie stuff, the new Mythic Map Pack will be the last map pack, and ODST will be the last game proper.
Bungie doesn't see the end of its involvement with the game as the end of the game's life, however. "With Forge and the Mythic map Sandbox we're already seeing the community stepping up to create some great new maps and gametypes that will offer more variety and longevity to the game down the road," the studio said. "The future of Halo 3 online will become more and more defined by the people who play it."