George A. Romero's 1968 black-and-white low-budget shocker "Night of the Living Dead" is the scariest film ever made. There's something about being trapped in a lonely farmhouse while dozens of living dead cannibals are outside trying to bust inside so they can eat you alive that always gets me. There are lots of film critics and analysts who love to drum up the political sub-texts of the film all the time (that it was a commentary on the United States' involvement in the Vietnam War, etc.) but I never bought any of that. The only thing I ever thought about when watching this movie is just how horrible it would be if the world was suddenly infested with a horde of living-dead zombies bent on the complete annhilation of the living.
No zombie film was ever as terrifying. In fact, no movie in the history of time was ever as terrifying as this masterpiece.