8. Hellboy (Hellboy Movies)
I will forgive the leather pants by virtue of the fact that, whilst worn by a red devil-looking creature, they actually look acceptable. Not great, but acceptable. However, it is the open trench coat with nothing underneath but his rippling torso that really makes this look cool. The trench coat is all kinds of awesome, and even manages to draw attention away from the fact that it's being worn by an otherworldly creature (it also serves as a means to hide the fact that Hellboy has a tail). While it's not a 'costume' as such, it's one hell of an outfit for ass-kicking.