Speaking of "slow" jump scares, the one that still haunts me is in Kurosawa's Kairo (the original Japanese source for the terrible American remake called Pulse). There is a scene in a basement where a woman appears out of a shadow and then walks toward the camera (and a frozen in terror character) that is so damned…

Anthony Ingruber should be in the discussion.

Lansdales's 'Night They Missed The Horror Show' is one of the most horrorific stories I've read by any author. It's been at least 15 years since I've read it and I can still remember passages verbatim.