Mighty God King has ranked all 32 Marvel movies released since 1998 and while I haven't seen all of the entries, I think he has the others in about the right order. I just saw "Winter Soldier" a couple of nights ago and I am still pumped up about it. Usually I think of "Iron Man" as the top film, but he has a point about the closing act being fairly weak, particularly after seeing the Winter Soldier fight scenes.
How about you, where would you rank them?