I have to agree with you, at least as the most horrifying movie I've ever seen. I actually stood up and started to leave the theatre, I didn't think I could handle it, but I found the story so compelling I sat back down. Sloth is what made me almost leave, so disturbing...
As far as good fun screamer scary movies, I always loved watching the original Halloween and the first sequel, When a Stranger Calls, the first Nightmare on Elm Street, and the original Prom Night. There was also a made-for-TV movie I used to watch as a kid called This House Possessed - I am sure it was terrible, but I loved it.
When we were kids, Stephen King's "IT" was the big baddy... I still can't stand clowns. :shock:
My poor kid brother went through a period (when he was about 5) where he refused to go to the bathroom alone because he was convinced that "Chucky" was going to pop out of the toilet and get him. Our older brother had let him watch the Child's Play movie, and it really made an impression on him...
Mr. Sardonicus; nothing scarier than a movie when you are young and you and your best friend have to walk home and your older brother and friends wait for you to scare the daylights out of you, makes a lasting impression.