Obscure - or not so obscure - sites I regularly visit and wholeheartedly recommend.

Dark, scary, depressive

Opacity - great pictures of abandoned places
Abandoned places - Even more abandoned places
True Crime Daily - if you happen to feel too fine and too safe.
Murderpedia - Enormous library of violent crimes

Fun stuff

The L-Space Web - Discworld.
The Oatmeal - crazy, smart, amusing.
Lotus Rose - crazy, smart, darkly amusing.
Vlad's Little Hole In The Wall - compulsory reading for goths, highly recommended reading for the darkly inclined
Evil Guide - So, you've decided to be evil? :D
Happy Tree Friends - the syrupy-sweet little creatures ALWAYS get what they deserve.

Sensible stuff

Online literature - Just in case you want to read.
VDocuments - Just in case you want to read more :)
GuitarNoise - learn, learn, LEARN!