I watched The Cook, the Thief, His Wife, and Her Lover with a group of friends and it is absolutely one of the most vulgar, offensive, and disturbing movies I have ever seen.
It makes Saw looks like it should be in the family entertainment section.
I have two scariest movies. One is Hitchcock's The Birds, and the other is the the Dr. Who episode called The Empty Child/ The Doctor Dances. I'm not sure if Dr. Who counts though. Either way, The scariest is probably The Birds. *shudders while thinking about man with eyes pecked out.*