I've played pretty much most all of the games mentioned. I like Resistance 1 but Resistance 2 was a let down since it didn't have much of a story nor did it expand the Resistance universe much and it felt short and it wasn't a big improvement. Gears 1 & 2 is nice because the story progressed and it did have some intense moments/firefights. KZ2 was a bit forgettable except for the graphics. COD2 was pretty good, COD3 was ok, COD4 was the complete package, COD WAW was better than I expected, and MW2 I have but haven't played much yet.
I am only talking about solo campaign and not MP though.