Xbox 360 exclusive even bigger than Gears of War 3 for X'mas 2011?

[SecondWar]

For all the people saying Halo 4, id say thats unlikely ever to happen. Halo Reach more or less is Halo 4. Yes I know its not a sequel to Halo 3, but Halo 3 was the end of the trilogy so its ended there. If they continue the storyline the game will probably have a similar name style to Reach eg 'Halo: insert new series title here', similar to how Call of Duty went 1, 2 3, 4 and then the direct sequel to CoD 4 refreshed the numbers.