For better or worse, this is the one that started it all. Regardless of your opinion on Call of Duty's annual entries now, cast your mind back to when Modern Warfare was first released. This game completely reinvented a popular first person shooter by taking it from World War 2 straight into the modern world, bringing with it new technology, weaponry and the type of experience that turns a franchise from a mere household name into an unstoppable juggernaut. Plating MW's multiplayer for the first time was also magnificent. This game mode basically set up what was to become one of the most played multiplayer components in history, with millions of gamers worldwide competing against each other in addictive shootouts. If you think Call of Duty has lost its way nowadays, just remember how good it felt when it wasn't shoved down your face every year. Modern Warfare is a classic.