Computer game fans might’ve been mad for a few downgrades compared to the previous version, but Modern Warfare 2 still became on of the most profitable pieces of entertainment of the decade (if not of all times): according to Activision, Call of Duty: Modern Warfare 2 just surpassed $1 Billion in retail sales worldwide. Can I get a “WOW”?

In its first five days alone, the game sold an estimated $550 million worldwide, outpacing five-day worldwide theatrical box office gross figures for such films as Avatar, Harry Potter and the Half-Blood Prince and The Dark Night, according to internal Activision estimates.

“Call of Duty:Modern Warfare 2 has exceeded our expectations and shattered theatrical box office and video game records,” said Robert Kotick, CEO of Activision Blizzard. “There are only a handful of entertainment properties that have ever reached the $1 billion mark, which illustrates the power of the Call of Duty franchise and mass appeal of this game.”

No wonder that we’re hearing more and more rumors of a Call of Duty MMO created by Infinity Ward…