This is a list of movies only where a severed head was used. They are mostly horror films but there are some suspense, fantasy, science fiction, adventure and mystery films in there as well. Which was the best use of a severed head in a film?
To suggest some more, the most notorious devices for chopping heads off is here. No films under 12,000 votes and 6.5 rating unless the film had an exceptionally good use of a severed head that is memorable.
Believe me, once you see a severed head rolling down a staircase in a movie, gore in a horror movie will never scare you again.