The last 2 or 3 call of duty games sucked. It just turned into a bunch of hackers and unrealistic bull shit I didn't have time to put up with.
Call of Duty games are extremely unrealistic, and if you are looking for a game that will be realistic etc. wait for BF3. I assure you the guns on it will be better, and there will be a more mature player base.
CoD fans: Why do you guys still even believe in the CoD's anymore? They literally make map packs like every month, and they come out with new games like literally every year. It has gotten really old and annoying.
If you are looking for a quality multiplayer game, get BF3. You might even be able to play it when you get it as well. Will take you forever to get into a server the morning mw3 comes out. It also comes out a month or two earlier than mw3 as well.
If you are looking for a quality singleplayer game, get The Elder Scrolls V: Skyrim. It will be intense, and more than likely earn game of the year awards.