Happy Halloween y'all!
I actually saw it not too long ago but my favorite might be Halloween (1978). I was really impressed by the direction of it. I'm not too familiar with Carpenter's work or horror in general for that matter but I just felt the creativity and vision of the man behind the movie. Great film making.
Of the more contemporary works, I'd have to go with It Follows. I just love the tone the music and cinematography creates. I recognize the last act is very poor but the ride is as good as any modern horror film. I think Hereditary might be better overall but it's almost too recent and I need to wait and see if it stays with me longer.