Horror is one of the most interesting genres in horror.
It can be stupid, bombastic, sickening, insane, gore-ridden and many other things. Both Eraserhead and A Nightmare On Elm Street come under the same banner, but both films are dramatically dissimilar. Same can be said for Evil Dead, Rosemary's Baby, The Exorcist and Alien.
But my favourite horror film, and favourite film in general, is the twisted masterpiece that is The Shining.
I'm going to assume you all know the story, but I'll give you quick overview of the plot:
"Jack Torrance, a writer and recovering alcoholic, takes a job as an off-season caretaker at the isolated Overlook Hotel. His young son possesses psychic abilities and is able to see things from the past and future, such as the ghosts who inhabit the hotel. Soon after settling in, the family is trapped in the hotel by a snowstorm, and Jack gradually becomes influenced by a supernatural presence, descends into madness, and ultimately attempts to murder his wife and son."
The story is just magnificent. A rather simple concept that in wrapped in layers upon layers and backstories. This is in full-effect in the most isolated of scenes.
But it doesn't stop there - Kubrick's genius when it comes to avant-garde imagery is all over The Shining. Even concepts that might come as hokey or cheesy (the blood in the elevator, the bear costume) are truly terrifying. His nit-picking eyes are at full use in this film, and it benefits from it in extraordinary fashion.
From the masterful acting work on the small cast (which only adds to the paranoid nature of the film) to the perfect scenery and scares, The Shining works on all levels. This is a film that I would recommend to people who horror films, but also films of the most experimental variety (Eraserhead and The Seventh Seal immediately come to mind). A must-see masterpiece.