Partly inspired by the brief discussion on it here, I have watched "The Exorcist" this evening.
I've seen it two years ago and then maybe three or four years before that (the first time I thought it was shitty, the second time it really struck me)... So it was basically a new experience.
I was familiar with the plot and setting, I think I have seen just about every parody on every part of the film, but I must say this is indeed a really scary film. However, it is one of the cases where I wish I had been around when it was first released.