IMO 4, without a doubt, Modern Warfare was the best out of the bunch and any CoDs after that all others were just awefull.
The storyline was amazing. The Multiplayer concepts were amazing. Graphics were great for the time. Oh, and the mods man!!! found amazing clans through cod4 and cod2. Just delightful ^_^
Cod1 was the bomb, and cod2, the most amazing games evaaah.
cod3 i never played, not for pc so i figured meh.
Now let us talk about 'World at War'... wow... The.Most.Pathetic.Game.Ever.
I mean seriously, The sounds effects were just terrible and the storyline was pretty meh...
MW2 was meh, cod4style but still in the shadow...
Black Ops was like laughable... same as WaW tbh...
MW3 was just MW2 with new guns
and have not played Black Ops 2 just yet, and not planning to!!!
Anyways that's my opinion on the matter anyway ^^ Top 3:
-Cod4
-Cod1
-Cod2
Chunc.