Or any derivative, such as darkness, darker, darkened, etc.

Song: "Dark Chest of Wonders" by Nightwish
Band: Dark Sanctuary
Album: Dark Passion Play by Nightwish
Genre: Neoclassical darkwave

BQ: Kate Bush or Tori Amos, who do you prefer?
Darkwave, dark ambient, dark cabaret, I'm sure you can come up with a genre. If there's not many to choose from, that makes it easier to choose. ;D

song – Dark Wave – Stephen Malkmus
Band – unfortunately I can't think of one.
Album – probably Oingo Boingo's Dark At the End of the Tunnel

I haven't heard any dark wave music that I can think of, but principly I could see myself liking it in theory. I thought that I once saw Elliott Smith classified as "Sad Core" which sounds pretty dark. I bet there is Dark Folk that could either go in the direction of someone like Leonard Cohen or Elliott Smith. I bet I'd be into a genre like that. All speculation though.