Walt Disney's The Adventures of Ichabod and Mr. Toad has been a Halloween staple since early childhood, when I would fast forward through the Wind in the Willows segment so I could get to the "good stuff"... The Legend of Sleepy Hollow.
An aspect of this adaptation of Irving's original tale that thrilled me as a child is the introduction of the Headless Horseman by way of his terrifying, ghostly cackle. IMDB credits Billy Bletcher as the voice actor behind the Horseman's laugh. In my mind, there is no other evil laugh that comes anywhere close to this one.
Listen to a collection of the laughs below (0:30). The first half is without echo, but the second half is how they are heard in the film.
