john carpenter's the thing ,waaaay scarier than the exorcist.

Hertz32

Same goes for DUNE. as I recall there's only 1 shot where CGI is properly used and thats great too. 
I'm aware that others will disagree however. 

chillidoggy

'Alien' scared the crap out of me the first time I saw it.

Monkeybone

I have to be honest, The Exorcist didn't scare me in the slightest, in fact I found it quite boring.

Bellycaster

Both fantastic films. The Exorcist "disturbed" me more I think (If that's possible), The Thing was just like "What the Fuuuuuuuuuuuuuuck" sort of scary.