Every person will have their own scariest movie, something that deals with their phobias or with things they might believe in... for example if you see a movie about vampires and you believe in vampires, that will be your scariest movie.
Jacob's Ladder! actually I don't know that it's so much scary as it is whacked out. Ghost Story - at least when you are 8 yrs old and your parents take you to see it just b/c part of it was filmed 30mins from our home town in Vermont....Yeah, I slept with a (baseball) bat that night!!!!
I'd say when I saw the Exorcist Directors Cut at the cinema a couple of years ago, that would be the most uncomfortable/scary 2+hours. The Ring at the cinema also freaked me out, but seeing it again on dvd it just didn't have the same effect on me. I think it was the sound at the movies that did it.
No matter how many times I have seen the movie, The Exorcist just puts a whole different perspective on what a real thriller is. The damn movie is decades old and even still when I see it, I'm like wtf... and get the occassional chill. Anyone remember The Howling?
Definitely "The Exorcist"! I saw the movie when I was about 8-years-old, and have been tormented by it ever since. That movie is the sole reason I am afraid of the dark - at age 31! No movie will ever top it in scariness - it plays on real events; not like "Friday the 13th", or "Nightmare on Elm Street", which are so far-fetched, they're almost funny instead of scary.
I would say the most recent scariest movie ive seen has got to be "The Blair Witch Project" even tho i saw this a couple years ago, nothing has beaten it since. Due to its realism, and the cheap budget, i find it was a great success...
I would say it depends on person to person, but I was scared watching the ring and grudge (but not ring 2)