I think I'd say Rosemary's Baby. Honestly I cried like a crazy person through most of it and for some time after. It stayed with me for ages. It still gives me shivers. I mean it was a little unsettling and I don't watch a lot of horror but mainly it was just so desperately, desperately sad.
Anyway apologises if I'm covering old ground here...
Anyway apologises if I'm covering old ground here...