The Real Ghostbusters.
Episodes like the Collect Call of Cthulhu and Ragnarok and Roll and No One Comes to Lupusville (the episode where werewolves battle vampires!).
J. Michael Straczynski even worked on the show, I'm not a huge fan of his work these days, but he's no hack.
Yeah, it was a saturday morning cartoon, but it really impacted my preference for horror and the macabre. And action and comedy.