Currently I own just MW, MW3 and Black Ops, but in the past I've bought/owned

Call of Duty: Finest Hour (PS2)
Call of Duty 2: Big Red One (PS2)
Modern Warfare (360 x2, PS3)
World at War (360)
Modern Warfare 2 (PS3, 360)
Black Ops (360 x2)
Modern Warfare 3 (360)

I'm never buying another Infinity Ward made Call of Duty game, but I do plan on buying Black Ops 2 because I still have trust in Treyarch.

None
rented MW2 on the ps3
and played Blops on the 360 at work...that's about it

Yup. I didn't really get into call of duty until pretty recently. They are good games, but some people are just overly obsessed with them.

Call of Duty 4, Call of Duty: WaW, Modern Warfare 2, Modern Warfare 3.

4, not including multiple copies.

i bought cod 2 and modern warfare 2 but i only own modern warfare 3 (i won it in an advent calender of a german gaming site and i still didn't open it. i own it since january lol)

mw1, 2, 3 and BO

I own Modern Warfare 2 and 3. Fun multiplayer.
Borrowed Modern Warfare 1 for single player.
Bought Black Ops. Didn't like it and traded it for an electric shaver at best buy. Good decision.

As for people who don't like the franchise. I get that the gameplay is quite similiar but that can be said for quite a lot of successful games. They do add new features with each iteration. The support for MW3 has been good so far. They add new modes and soon not elite players will get 2 new maps. Not much but still something. Also no one forces people to buy these games so i don't quite understand people who talk crap about them.

Will most likely skip the one this year. Haven't played the old pc ones so will try those.

Call of Duty: Classic (XBL)
Call of Duty 2 (360)
Call of Duty 3 (360)
Call of Duty 4: Modern Warfare (360)
Call of Duty: World at War (360)
Call of Duty: Modern Warfare 2 (360)
Call of Duty: Black Ops (360 + Wii)
Call of Duty: Modern Warfare 3 (360)

None. I played with a friend, but it never seemed interesting.

Only own MW1&2. I've beat 2,3,4,WaW,and MW2.