I really wouldn't call Freaks a 'horror' movie. I'm not entirely sure how to classify it. It definitely isn't horror, though. I would most likely consider it just 'drama' or 'suspense'. It's a great movie, that is unique, and definitely in a class of it's own.
I remember watching a really old Hammer movie called "The Tingler" when I was a kid and being pretty surprised it rattled me more than the Halloween/Elm Street movies. Don't really remember much of the plot just the fact it had a psychological effect at the time.
I love the Hammer movies, even the absurd ones. Though 'Captain Kronos' is hands down my favourite, even though it's not a typical one.
Here's another 1970s classic: Magic. It's got Anthony Hopkins, a ventriloquist's dummy and a script by William Goldman. What more can you ask?
I'm going to watch every horror movie posted in this thread if i haven't already watched it. now my new favorite movies are modern day movies that are made to look like they are made too look like the 70s. it follows being a great one