Would 20m more likely be the entire sales of the trilogy rather than the 3rd game?

There would be a good chance that Frank O'Connor wanted to have creative supervision over all Halo games, not just 1 of them, so working with MS gives him supervision over Halo Wars, Halo 4 and Peter Jackson Halo. Still, I'd be surprised if Bungie were doing Halo 4, didn't they already say they didn't want to do it and wanted to try someone new instead?

I dont understand why Bungie dont want to do Halo4? why is it that they must abandon what they created, Its like John Carmack Saying, I dont want to do another Quake or Doom i want to try something new? not to mention the amount of money this franchise must bring in for them, why cantthey make halo 4 and something new????

For everyone person who complains taht halo 3 is pants, there are 3 waiting to beat the crap outta that guy, i for one think halo 3 show sthe best online experience LIVE has to offer (cept maybe COD4)

He did, Carmack is doing Rage just now ;)
It's another team that is doing Quake Live (and of course Splash Damage did Quake Wars)

MS owns the rights to the Halo Franchise, not Bungie. So O'Connor going over to MS to more closely work on the series makes perfect sense. They(Bungie) may be working on Halo 4 right now, but it is directly to MS they are answering to. So it does give O'Connor more control over the Halo series. Like mentioned, before it also gives him say in other Hao projects, Bungie probably doesn't even really have say about anymore, after the rights to Halo swapped hands.

Your not serious...i played halo 3 on legendary twice and saw the ending..twice...just to try to relise what was going on...unfortunatly.i cannot see a halo 4 coming from the evidence..unless a confirmed peice of info about halo 4 is released im staying rather neutral...but i will sya this "chief wake up" does imply that there is another enemy..and i wouldent be surprised if in halo 4 (if there is one) that the chief is looking for a way back to earth from the planet in the last scene...halo 3 had a quite unfinished end..the arbiter leaves and thats it? no way...i think the planet they were coming towards is the elite homeworld..which has been destroyed by rebel humans...and the arbiter try to kill the chief...and i think sgt. forge from halo wars is the chief....and his past is getting revealed.