Jigoku Shoujo(Hell Girl) was the first anime that I ever really got into. I watched it for the first time in my high schools anime club and it was real dark and serious.
For those of you out of the know: This anime is about a mysterious girl called Ai Enma. Access the website hellcorrespondence.com apon midnight's veil and enter the name of your tormentor. She will ferry that person's soul staight to the depths of hell. "However, there always has to be a price. When you die your soul will also be sent to hell. You will never know the joys of Heaven, your soul will be left to wander in a world of pain and agony for all eternity."
So yeah, pretty serious stuff. The art is really good and the music is amazing. I highly recomend watching it.
I do not own this, I am just a fan