The Exorcist.
Excellent, excellent film. Almost traumatic to watch, for reasons I can't explain why. There are films that are scarier than this that don't leave half the impression. But of course everybody here is probably already familiar with the effect it can have.
A bit of news for people who want to see it. Netflix has added it to their streaming catalog, and as I just watched it I can confirm that it is the theatrical cut, which is a plus in my book. None of the added music, pointless hospital scenes or spiderwalk (although I did miss that one) are present. With all this in mind, it does seem to be based off of the transfer used for The Version You've Never Seen onward. ie cleaned up video quality and clear colors, but the cut is the theatrical, and while it's been a while since I've seen the film, I *THINK* damien's demonic eyes at the end are original as well. I wasn't aware something like this officially existed? I thought all HD/restored versions of the film were the "special edition"? But I'm not sure, either way Netflix has the theatrical in great HD quality so go watch it.
The only thing I really miss (other than the spiderwalk... but that doesn't bother me a whole lot) from the extended version is the Exorcist and Damien's dialogue about Pazuzu choosing to possess raegan to show them the evil beast within them all. Those lines were great and in my opinion changed the tone of the ending.