Back in my youth, I spent hours pawing through the backs of record stores trying to find albums by people like Brian Eno, Pete Namlook, FSOL, and other strange electronica. Then the internet came along and opened up whole new worlds of music. Here's my favorite music to code and drift into space with.
Sleepbot. I first discovered the Sleepbot Environmental Broadcast in 1998, and a decade later it's still my station of choice. Rarely repeating, it sometimes plays hours of of street noise, leopards purring or strange medieval chants, but more usually has a hand-picked selection of haunting electronic tunes. Dan Foley's has a wonderful ear (or at least one that almost always agrees with mine), and he's introduced me to some of my favorite artists like Stars of the Lid, Windy and Carl, Solar Fields, Sigur Ros, Tear Ceremony, and Papa M. Even better, he's accumulated notes on all the artists he plays in the Ambience for the masses encyclopedia.
DroneZone. A lot newer and less eclectic than Sleepbot, I'll sometimes switch over to see what I'm missing. I'm not surprised as often as on Dan's stream, but they do have some dreamy mixes that hit the spot.
Spheric Lounge. With dozens of sessions, all produced live, these spaced-out Germans have let me fill up my iPod with mp3s. It's useful for the rare occasions when I don't have internet connectivity, but more importantly gives me a solid supply of music even if civilization collapses around me. The covers alone are worth the visit.
Low Light Mixes, Somnia, Hydrogen Cafe. I've run across a few artist blogs with long-form mixes. Some of these haven't been updated in a while, but it's well worth listening through their archives.