I think Halo Reach will be another high maginitude game, blowing out the competition around it, since it returning back to the original FPS Halo of old, and adding a new engine, different take on the story, and most likely, learning from the issues people had with ODST, particularly the length of the campaign.
ODST sold 2.5+ million despite being a glorified expansion. Anyone who thinks that, Reach will sell below 200% of ODST, is full of wishful thinking.
Beat MW2? No, it won't, because that game has a gargantuan following. Not even a Halo game can achieve those obscene numbers. No game this gen will sell as fast in a short time (maybe lifetime, like a New Super Mario Bros Wii). And don't give me this "God of War will" crap, that's fanboy talk.
God of War, for it's violence alone, will not reach the mainstream like other big time selling games can - ESPECIALLY Mario. Also, Halo does a good job keeping the rating down to at most, a Teen rating, which is a smart move.
