D.N. Angel is cute. I love it. It's about a 14 year old kid named Niwa Daisuke. According to a legend in his family, when a boy reaches 14 he turns into the Phatom Dark Theif, Dark. He won't have too much trouble with Dark, but he turns into him whenever he feels love. Of course, he has feelings for someone, her name is Risa. But Risa loves Dark. And Dark loves Rika, Risa's twin sister. So it's one big love triangle, plus loads of fantasy.
I like this one, don't know why
Has info, and more
Into the Darkness, a shrine to Dark Mousy