If you are into Dark stuff AND Gothic, it is very very likely that you'll be into victoriana. This is my last discovery.
This very resourceful site is the creation of writer and victorian afficionado, Lee Jackson. Anything you want to know about victorian London, you'll find it here. History, economics, personal stories, literature, maps...Everything! And if you can't find what you want, you can email the writer.
It is a great page for both research and pure nosiness. His blog is worth having a look too. It includes more interesting links.