In random order a few of my favorite
Evil Dead
Drag Me to Hell
Let me in/Let the right one in (REALLY liked both the original and english re make both)
Re-Animator
The Cabinet of Dr Caligari
Freaks
Ginger Snaps
Shawn of the Dead (kinda counts as horror? LOL)
The Thing
Jaws
Phantasim
Night of the Living Dead/Dawn of the Dead
The Shinning
Grindhouse
Have a bunch more but kinda long list already