Halo has dominated Xbox Live since Halo 2 hit Xbox, even topping the 360's online gaming lists (until Gears of War), but the third game's domination of Microsoft's online servers has been put on hold by Activision.
Last week, (beginning Jan 14), Call of Duty 4 managed to knock Halo 3 off the top spot on the list of most played Xbox Live games.
Master Chief was forced to settle for second place, with Guitar Hero III (another Activision title) coming in third, and Gears of Warin an ever solid fourth.
Also revealed by Major Nelson's official XBL stats is Metal Slug 3's top-selling turnout. Boogie Bunnies came in second - which is a suprise, considering that most casual gamers own Wiis.
Jan 22, 2008