I am not a horror movie fan but, I have seen many of these movies and I agree with the consensus that The Omen is the best of the bunch listed here.
The Exorcist is almost comical in its poor production quality. It was so poorly produced and directed as to make it a farce. Too bad. Because the premise of the movie, based loosely on an actual exorcism, so we are told, deserved so much better.
I remember audiences being freaked by The Exorcist when it debuted. I never saw it, but that’s what the news was going on about at the time.
A good folk-horror double-bill is 1973’s “The Wicker Man” and last year’s “Somartag”