I promised fila_desu I'd share this song, it's the duet Soubi and Ritsuka from Loveless sing.
Ritsuka's voice actress is the amazing Minagawa Junko, so it's almost a given that the song is good. She nailed Ritsuka perfectly, I'd watch the anime just to hear her say 'Soubi'. You won't understand until you hear her say it... MY GOD.

For anyone who wants it, here it is: ENTRUST- Soubi&Ritsuka