Being that All Hallow’s Eve is fast approaching, thought I’d point out the Incredible series that Lowell Francis did over it his excellent Blog, Age of Ravens. The history of Horror RPGs Seven parts so far, that is part 1
As for all time best Horror RPG, Kult gets my pick,Swedish horror like almost two decades before Let the Right one in hit the US.
Speaking of Swedish Horror, check out the books of the author of Let Me In, John Ajvide Lindqvist, who has written a host of horror books.