Agnes Obel has been a huge favorite of mine for a few years now. Her albums, Philharmonics and Aventine, are absolute dreamworlds. Her heavenly, soothing, elegant voice and the gorgeous melodies always bring such a beautiful, calming vibe to my day - I also listen to her a lot when I can't sleep. She should do an album of lullabies. :)
It's so hard to choose a favorite Agnes song - Dorian, Brother Sparrow, Over The Hill, they're all stunning - but I always go back to the tune that first introduced me to her - Riverside. Listen below. Isn't she the dreamiest?