The Shining
The Exorcist
Halloween
Night of the Living Dead
The Ring
Salo is definitely disturbing. I saw it in a theatre, and about 2/3 of the audience cleared out at one point or another.
In no particular order:
The Shining
Creepshow 2
Pumpkinhead
Re-Animator
Event Horizon
Poltergeist (it’s terrible, but I was 9 when I saw it)
The Exorcist
Alien
Halloween
Swept Away (the horror, the horror!)
The Exorcist
The Texas Chainsaw Massacre (original)
The Ring
The Shining
Session 9
No suprises here…
The Exorcist
Night of the Living Dead
The Ring
Carnival of Souls
At the Mouth of Madness