THE most iconic costumes in the history of film!
I don't think "Star Wars" has any competition. People all over the world can look at a Darth Vader dog toy or hand lotion dispenser and know exactly what it's referring to, and I don't think that any film ever has produced a costume as instantly recognizable as Vader or a stormtrooper.
Still, I'm willing to consider any other candidates. Any costumes more iconic?