My favourite scene is the one in "The fearless Vampire Killers". I've seen this movie at least 20 times and I never get bored of it. The scene I'm going to speak about is very cleverly done. The main characters (Roman Polansky among them, that is also the director) are intruders into Count Von Krolock castle. They are dancing among a lot of vampires at a ball when suddenly, only they can be reflected themselves in a big mirror so everyone finds out they aren't vampires and a long final chase begins.

It's like a lesson in both, comic and horror directing. If you've never seen it, you really should.