Soma FM is one of my favourite things. Their stations are among my top listening while working. The lack of ads/interruption and excellently compiled playlists make for wonderful listening that truly augments my mood and ability to concentrate.
Another recommendation :
I used to listen to "Bluemars - Music for the space traveler" stream, but it has been defunct[0] for some time. However, it seems someone is trying to revive it there [1]. It is really great to use as background when coding. Eerie and inspiring.
They are amazing, and afaik live off of donations. As each of you guys discover Soma, please consider a small donation to the station to keep them going.
So bizarre. I remember listening to Groove Salad when I was probably 14 years old. Now here I am, 11 years later, living in SF, and I get reminded of it on a random HN post.
I personally don't really listen to sf1033 at all, but figured I'd toss it in since I figured HN probably has a skew toward that area ;-) For more ambient, I'm usually listening to recommendations by,
http://somafm.com/sf1033/
Ambient music mixed with the sounds of San Francisco public safety radio traffic.
[ SomaFM Mission Control ]
http://somafm.com/missioncontrol/
A mix of ambient and experimental music mixed with the historical sounds of the space program.