So this Friday I'm inviting some friends over for a horror-movie marathon as a year-end party! I'm excited, because I've never really watched horror movies. I did get a small taste of one though- I saw maybe half an hour to and hour of The Boogeyman 2, but I was too freaked and grossed out to continue watching it.

We're planning to start with the least scary movies and work our way up to the scariest. Here are the movies we're planning to watch:
Prom Night
The Exorcist
The Ring
and I'm thinking maybe A Nightmare On Elm Street (if it's out... I don't keep track of these things.)
Can anyone suggest any super-scary movies for us to watch? And if you've watched any of the movies above, can you tell me if they're really that scary or not? I don't know which order to watch them in. I don't think I can stand Saw- too much gore. I know there is gore in other horror films as well, but Saw is supposed to be one of the goriest films out there, I've heard. My friends have told me about it.

Thanks.
Edit- I just watched the trailer for The Exorcist, but it doesn't look that scary... wondering if I should watch it or not?
Another Edit

- and I forgot to add, we're watching Shutter Island too! Has anyone here watched it? My mom says it's depressing. o.o