Man, the golden age of CoD imo. Tough choice between Modern Warfare 2 and Black Ops 2, those are my all-time favorites. I'm probably going to give the ever so slightest edge to Modern Warfare 2. 

About what I expected. MW was something special in 2007.

COD 4: Modern Warfare was the gamechanger and one of the few COD games that deserves a spot on a greatest games of all time list.

That is a lot of Call of Duty games in one generation! I haven't played any of them but wow so many games!

For me, it's World at War.

It really captures that sense that war is hell and feels like a desperate and morally ambiguous struggle for survival as opposed to the more detached shooting galleries of most entries in the series. I feel it's the most intense and truly mature entry in the series.

Black Ops II gets an honourable mention for its branching narrative paths, interesting near-future setting and technology, and the best story in the series in my opinion.

The first two Modern Warfare games were excellent. I also have a soft spot for World at War or CoD3, since I like World War 2 shooters, it's shocking how quickly those dissapeared after a while...

Especially considering how prolific they were in the 2000s. Modern Warfare seemed to almost kill WW2 shooters overnight.

Have you played COD2?

I have, I also enjoyed it. In retrospective, CoD 2 was better than 3, honestly.

Poor Advanced Warfare, no love for it.
While it's not as good as MW, World at War, of Black Ops 1 & 2, I thought it was still pretty good and better than COD 2/3 and MW2.

Well, Modern Warfare probably had the biggest impact, but my personal favorite is Black Ops.