What is this anime where the girl wears a ribbon wrapping her hair like double helix and wears black dress?
Google reverse image search says Elemental Gelade, and the girl is called Reverie Metherlence.

A brief description from Wikipedia:


  The fantasy adventure is a tale of a group of five who are on a journey to Edel Garden, the birthplace of mystical beings called Edel Raids who are described as "living weapons".