Update: The PSN Store is holding this event as well.
Activision cuts the prices of all Call of Duty titles on the Xbox Marketplace. So, if you’re new to the Call of Duty series, you should get at least Call of Duty 4: Modern Warfare. Personally, I prefer World at War because it was my first Call of Duty experience, and then I went back to CoD 4, but I acknowledge the fact that Modern Warfare 1 is the superior game.
Here are the prices of each game,
Call of Duty 2 $19.99 (You can find it in bargain bins for less.)
Call of Duty 3 $19.99 (You can find it in bargain bins for less. Not recommended by MP1st)
Call of Duty 4: Modern Warfare $19.99 (Good price. Highly recommended by MP1st; however, hold until I test how the mp is. I hear hackers are ruining it.)
Update: TDM is currently plagued with hackers. Might have better luck in objective based games.
Call of Duty: World at War $19.99 (Good price. Recommended by MP1st)
Call of Duty: Modern Warfare 2 $39.99 (Same price as Amazon. Recommended with reservations by MP1st)