Let's see, I don't think these have been listed yet... The others are all good, that have been mentioned so far. Especially Ergo Proxy and Monster.
Shingetsutan Tsukihime isn't new, but it's about on the level of Fate Stay Night in darkness...
Shakugan No Shanna is another not-so-new one that I really liked.
Claymore is shaping up to be a good anime on the "dark" side of the spectrum. Some have compared this one to Berserk. I don't know if that's valid or not, though.
I don't know yet, if
Sola is going to turn out dark or not, but the end of episode 1 doesn't bode well for lighthearted hilarity, anyway!
