Halo 3 was the most popular game on Xbox Live in 2009, but spots 2-4 in the list were occupied by the last three Call of Duty games.
That's according to Major Nelson's blog, which is running down the top 20 Xbox Live games of 2009 in various categories.
In the retail games list, Halo 3 led from Call of Duty 4: Modern Warfare, with Modern Warfare 2 in at three based on a couple of months - suggesting it was the most intensively played game all year - followed by Call of Duty: World at War and Gears of War 2.
Grand Theft Auto IV, Left 4 Dead, Halo 3: ODST, Fable II Episode 1 (the download title) and the Japanese version of Resident Evil 5 rounded out the top 10, although the US/European Resident Evil 5 also appeared in the list at 12.
Interestingly, while the Left 4 Dead 2 demo made the top 20, there's no sign of the retail game. Viva Pinata is another notable absentee.
Elsewhere, Battlefield 1943 was the best-selling Xbox Live Arcade title followed by the evergreen Castle Crashers, Trials HD, Hasbro Family Game Night (which is cheating, since it's several separate games) and Shadow Complex.
Finally, GTAIV was the most popular Games for Windows Live title, and Halo 2 was the top original Xbox title. Check out Major Nelson's blog for the full top 20 lists in each category.