I think this is the first SPN vid that ever got rec'd to me, and probably remains the most effective of the 'horror' style vids I've seen. Definitely not for the squeamish.
Everything's spookier in black and white, especially with the occasional red highlight.
Not exactly horror, but definitely grim. Another interesting use of black and white.
A more psychological kind of horror: Dean and his relationship to alcohol over the years.
A question to you all--several years ago, when I was in the process of rediscovering Supernatural, one of the early vids I came across was one centered on "Head of a Pin" and Dean torturing Alistair. As I recall, it was fairly simple editing, with a monologue voice-over from some other source--not the show. If this rings any sort of bells, could you give me a link? It would be interesting to watch it again and see if it still packs the same impact now.