the tracy chapman collection is a good album, or something else by Satie - 'Les Trois Gymnopedies'. David Gray - White ladder is quite chilled, or clubbed to death by rob d on repeat I used to find quite good (it's on the matrix soundtrack). Failing all that, Fireworks by Embrace. I find it difficult to get to sleep (a troubled conscience?) so I am somewhat of an expert!
I find "Shine On You Crazy Diamond" by Pink Floyd always works for me, preferably the live version from "Delicate Sound Of Thunder". It's about 11 minutes long, but i'm usually unconscious before the vocals even start. - The album "Reveal" by R.E.M sends me to sleep as well. Not that that's a bad thing, i like R.E.M!