I think you'd like the Administration Series. We have somewhat similar tastes. The final little push that got me to read was some art that I saw here:

http://lillithium.livejournal.com/89621.html#cutid1

and here (guh - love this one!!!):

http://elspethelf.livejournal.com/140948.html

The Attolia series might not be dark enough, but there was just something about it that came across as erotic, and I don't care much for het so that tells you how unique I found it.

Now if you like dark YA stuff, the first book in the Power of Five series by Anthony Horowitz (Alex Rider author) qualifies. The sequels aren't quite as dark, but I thought the first one was great.