What horror movies have in your opinion the most gruesome atmosphere?

Answer 1

Carrie, the HS prom scene and the follow up at Carrie's house were memorable (in my nightmares that is).

Answer 2

Ghodtsssssssssssss

Answer 3

I would say

Wolfman
Brotherhood of the Wolf
The Shining
Psycho
Halloween

maybe even the Great Expectations (1946), Gaslight.