I know what you're thinking, this game is the odd one of the bunch because it's based on real events and is generally non-fiction. However it's because of it's hidden gem, Nazi Zombies, that puts this game on the list for good reason.
Nazi Zombies is CoD's spin on a survival mode, with the spin that you're up against infinite waves of increasingly hard to kill Nazi Zombies, and in the case of some maps, Japanese Zombies. The mode is extremely fun and hectic as the waves start going up into the double digits. Originally an afterthought with only one level, this mode now has a total of 4 maps, the 3 included in DLC each being increasingly complex and given an added feature or play style that adds to the enjoyment.
If you love killing hundreds of zombies while trying to survive, with some friends to boot, this mode is for you, and the DLC is highly recommended, although I would suggest waiting until a separate pack comes out comprising of all zombie maps, or at least wait until a price drop. $10 just to play a zombie map is a bit steep, unless you like the multiplayer component that comes with.