Xbox gamers around the world can't get enough of Halo 2 the game has sold more than five million copies worldwide since its launch in early November. In total the Halo franchise has exceeded the 11 million unit mark, with cumulative sales from Halo: Combat Evolved, Halo 2 and Halo for Windows. Halo 2's new Xbox Live features are also proving popular, the global Xbox Live community has logged a record-setting 28 million hours playing Halo 2, which is more than any other Xbox Live game in the his…