What's the scariest movie you've ever seen?

I've had such a thirst for a great scary movie lately but I don't know where to start. I've only turned one movie off because it was too scary for me. Wait for it.........Candyman. Dang that candyman. That sorry sucker scared the crap out of me. I finished it but only after turning all of the lights in the living room on and waiting an hour. It was like I had just eaten and wanted to go swimming but had to wait so I wouln't get cramps.

To me, there's stupid scary, there's good scary, and there's scared to go to sleep and dream about that stuff scary. Blood and gore doesn't really scare me. You might think it's cliche but unexplained stuff like The Shining is scary to me. Those twins are freaking crazy. Shelly Duvall, Whoa! Yeah, when I think about it, it's the unexplained stuff that gets me.

I'd love to hear what you think, if not just to add some movies to the rental stack.