New to horror: What would you recommend?

I am looking for scary films to watch as I have recently started to enjoy them (I used to hate them!). However, I don’t want to much blood and guts/mass murderer types (although if you know of any really good ones then feel free to mention them), I prefer the more chilling stuff. Things that make the imagination work over time! I love anything to do with ghosts and have got Poltergeist (sp?) ready to watch. What would you recommend?