Man thats too easy!
It is easily 'The Shining'!! Jack Nicholson is amazing in this film, as is the entire cast. Sure its not overly scary, but its not meant to be a horror, as I see it it's a delve into humanity.
Also has the greatest line in a film ever, but you gotta watch both Jack Nicholsons face and the waiters when this line is said to get the full beauty of it
"Err..Mister Gradey, you WERE the caretaker here, I saw your picture in the paper, you killed your wife and kids and hacked them into little pieces..then you blew your brains out."