ArtCollaborators have (quite) a few gothic style character sets for many figures, plus a few vampire sets.

Damage, Inc. has lots of characters sets with extra props and backdrops included. Lots of dark fantasy and horror themes

Meshbox Design has horror architecture models available @ RMP, or complete sets at their own site, incluing a Lovecraftian village and the new Nosferatu building kit.

Trekkiegrrl has a few free, horror characters and lots of free props.

and a big shout out to one of my favorite scene creators, ratracer, who's models are of excellent quality and of great value. And another to Robotmonster, for the same reasons. 

-- Jeff