Looks like Skyrim will be just shy of 5 million on the 360 It might also outsell Battlefield 3 in a week or two. Damn that game has done work.
Also Halo Reach is essentially over 10 million in total sales when you combine VGC sales + digital copies via the Holiday Bundle + any other digital sales it has gotten over the 6+ months it's been on demand on XBL.