Call of Duty 4: Modern Warfare

Most everyone knew Call of Duty 4: Modern Warfare would be a smash hit, but few could've predicted the immense sales success Infinity Ward's incredible shooter has achieved.

After battering the competition (namely, Halo 3) on Xbox Live and becoming a huge draw on the PlayStation Network, CoD4 has shot its way into millions of hearts...millions and millions of hearts. It debuted with more than 2 million units sold between both the the PS3 and 360, and a mere two months later, ended up selling 7 million copies by the end of 2007. But while most games tend to hit a peak and then die out, CoD4 is showing no signs of "dying," despite finally getting knocked off the top of the NPD software list by Super Smash Bros. Brawl in March. According to a post by Infinity Ward's director of communications Robert Bowling at the developer's official blog, CoD4 has now officially reached the 9 million mark. That's a worldwide total number, but even so, it's pretty damn impressive.

So at this point, Grand Theft Auto IV will have to move fast to knock CoD4 off its lofty perch. Of course, given the fact that analysts believe GTAIV will sell more than 6 million copies worldwide in the first few weeks, this will probably happen. Doesn't take anything away from CoD4, though; that game has made an absolutely tremendous splash. Heck, it's a tidal wave!