Brian, I was the same way.  I was only about 7 or 8 when the "Amityville Horror" mania was all over the place... I also recall a segment on TV's "That's Incredible!" that seemed even scarier than anything else I saw in movie ads and TV spots for the actual film.  Some family relatives even had the paperback version at their home at the time, and just the cover freaked me out.  And when I caught the network TV showing in the early '80s, I thought it was the most disturbing horror movie my young mind could handle.

Today of course we know it was all bunk.  And the 1979 movie version is unintentionally hilarious in every other scene.  But even as an adult, the term AMITYVILLE HORROR can still elicit a split-second shiver that taps straight back to my childhood.

 

The first time I read it, I was not expecting that ending.  

There is a short film of it made in the late 60s that teachers used to show to classrooms that upset more than a few.    I think it's a story that really needs to be discussed if taught, not just "read this story, here's a quiz, let's move on". 

I read several of his stories on my commute last year and even on a brightly lit subway car, I was freaked out.  And I would not read any before bed.  They are amazingly effective.  

I'd be remiss if I didn't mention:

My younger sister was a voracious reader starting in her teen years, and she read a LOT of horror novels... especially Stephen King, Anne Rice, Peter Straub, Dean Koontz, you name it.  I'd stumbled upon a beat-up copy of JB's FEAR BOOK sometime in (I guess) the late '80s/early '90s?  Passed it on to her and said, "Tell me what you think."  (She knew of my own JB fandom at the time; and I knew of her own love for horror novels.)

She came back with a blank stare a couple days later and exclaimed, "Who knew that John Byrne could write such a fucked-up book???"

 

Stephen King's short story 'Strawberry Spring' always creeped me out in all the right ways.

Ania Ahlborn's 'Seed' is also deeply unsettling.

Dan Simmons's "The Terror" is a wonderfully heavy historical horror novel as well.