Madden. Sport games in general are pretty crazy when it comes to sequels. If any other genre was to release the exact same game repeatedly, just with minor roster altercations, they would get shunned. Yet EA Sports knows all they have to do is create one game and they can release it a dozen times under a dozen different titles and the mass will flock to each one. Sure each Call of Duty or Halo might sell more copies, but if you were to combine all the Madden/NCAA titles together that are basicly the same game, it'd beat out any other non-MMO title.