After a series of polls on social media horror fans voted John Carpenter the best horror film maker of all time. He beat the likes of Alfred Hitchcock and the creator of the Saw series. He is mainly known for the original Halloween film. While that might not be the most popular it is one of the films that true horror enthusiasts universally site as a classic. That alone would not explain his win. He has a long resume of films in the scary movie category.
Infographic Source: http://www.gorehor.com/best-horror-film-director-of-all-time/