Sorry COD4 fans, but it seems that COD couldn't keep it.
http://www.gametrailers.com/viewnews.php?id=5507Based on global unique players, Halo 3 sat in more Xbox 360 disc treys last week than any other game, at least when played online, says Xbox spokesman Major Nelson. Call of Duty 4 held the honor briefly two weeks ago.
To date, Halo 3 and Call of Duty 4 sales have been neck and neck, duking it out as king of the mountain over Xbox LIVE. Activision's multiplatform shooter was named the best selling game of 2007. Halo 3 is only available on Xbox 360, however.