I always trawl these posts looking for ideas - I pretty much watch horrors or creepy films exclusively (not interested in gore or torture porn), but I don't scare easily and find the majority of them fairly tame.
I definitely rate The Grudge, The Ring, It Follows, Martyrs (original) and Hereditary.
I quite liked the Paranormal Activity films, Babadook, Mama, and The Exorcist.
Largely unmoved by the Conjuring, Sinister, Insidious etc. Some are just crap - I thought Blair Witch and The Witch were way overrated, and as for Eli which I watched with great hope last night - jeez, what a dreadful ending. And Fractured is totally predictable.
I'm not really an old misery with no imagination but I long for something properly terrifying! Haven't watched Event Horizon, keep eyeing it on Amazon but sense I might be disappointed...??