Just walking in?  302 of the best "sleep songs" there are...  
http://www.imeem.com/mikeltrey/playlist/7X5jbHPr/sleep-music-music-playlist/

This is the more commercially available version of the previously linked IMEEM Playlist.    

I am not "Sleepy Sleeperson", I just really liked the playlist, scoured life for the songs used, and uploaded them, maybe, as a .torrent.  So some of the songs may be a little off, I corrected some, and maybe mislabled some of my own.  Also, it was updated recently, so my upload only goes to 302, there are now 303 songs in the playlist

From the link: 
Date Posted 1 year ago
Title: Sleep Music
Description: The best sleep playlist you'll find. Throw it on shuffle and drift away to the most sleep-worthy tracks ever created. Let me know if you have a suggestion for a song!less
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I know its tradition to put the tracks down, but this is my first torrent, and I'm not really sure how you do that, so I have resorted to typing the first 5 or so names, and letting you figure the rest out.  

[Song/Artist]
001 - Sleep - Plumb
002 - Flightless Bird, American Mouth - Iron & Wine
003 - The Finish Line - Snow Patrol
004 - MLK - U2
005 - Hawaii - Meiko
006 - Come Away with Me - Norah Jones
...
...
...
...
300 - Sleep - Blackalicious
301 - Sleep - Shelby Lynne
302 - The One I Love [LIVE R.E.M. cover] - Sufjan Stevens