Here’s a great article from Shock Till You Drop about would-be horror movies that never made it into production. Some of these sound great — The Van Helsing Chronicles, an adaptation of McCammon’s Stinger, Vertigo’s House of Secrets — while others sound downright dreadful. (Who wants to see Ice Cube fight werewolves in the film Stray Dawgz? Nobody. The answer is nobody.)
And for advice about good movies, listen to William Goldman (multi-Oscar-winning screenwriter).