In terms of per unit sales on a console by console basis, 2007 belonged to the Master Chief. Halo 3 was the top selling game last year in the U.S. with a total of 4.82 million copies. The Xbox 360 version of Call of Duty 4: Modern Warfare wasn’t far behind in third place with 3.04 million copies sold.

Unlike Halo 3, however, Call of Duty 4: Modern Warfare also is available on the PlayStation 3 and PC – and that fact alone likely helped Infinity Ward’s latest shooter become the top selling game of 2007.

Activision on Friday announced that Call of Duty 4: Modern Warfare was the top title in units worldwide in 2007, selling in excess of seven million copies since launch in November. This, if nothing else, demonstrates the sheer importance and buying capacity of the consumer market during the holiday season.

"We're very excited about this achievement especially given so many competitive titles this year," said Will Kassoy, senior vice president, global brand management, Activision Publishing, Inc. "Consumer and critics agree that Call of Duty 4: Modern Warfare is one of the best games ever created and further establishes Call of Duty as one of the premier brands in the industry. This ground-breaking game and franchise continue to establish new standards by which all other action games will be judged."

Call of Duty 4: Modern Warfare takes the franchise out from World War II and into present-day scenarios. The single player campaign, while short, offers a tight and intense cinematic experience. The real draw of the latest entry, however, is the game’s multiplayer component, which offers an innovative level-based perks. Call of Duty 4: Modern Warfare is currently the most-played game on Xbox Live, unseating Halo 3.