On iTunes you can go to Radio -> Ambient and there are a bunch of stations that play the style of music. I'm a fan of StillStream and Drone Zone.

Pandora also has a good selection of electronica and ambient music, and can store and learn what you like in a custom "station".

Here's a few related threads:

http://news.ycombinator.com/item?id=139901

http://news.ycombinator.com/item?id=167076

http://news.ycombinator.com/item?id=132026

I often listen to...

David Sylvian - Look for albums: "Camphor", "Alchemy" & "Approaching Silence"

Brian Eno - His Ambient collection.

and some varied classical music.

Strangely when I get into rhythm I tend to switch to something more "driving" like Radiohead

Well, my classical music (e.g. Beethoven 9th, Mozart Magic Flute that kind of thing) is too exciting, actually. What's yours?

Mozart as well. Also Bartok, Wagner, Stravinsky & Prokofiev are frequently played.

Sometimes I'll play trance ambient just loud enough to smooth over the environmental noise while coding: http://www.hbr1.com/perl/apax.cgi?run=jorbis&station=

Same for me. Trance is a good coding music. I get mine from http://www.trance.fm

Also check out http://ddance.fm

Brian Eno has an extra feature to his ambient music. Occasionally there will be a little note out of place, a tiny surprise. He says this is to keep you from falling asleep, or rouse you out of a daydream you may have fallen into. If you're really concentrating, this little "bump" in the music probably won't even register.

This is featured in "Music for Airports" (good for busy places), and "Discreet Music" (takes some getting used to, but fades solidly into subconsciousness after a few minutes).

Anything by Radiohead. Steve Reich "Music for 18 Musicians" - single hour-long track. Rachmaninoff "All Night Vigil". Cabaret Voltaire "Plasticity". John Coltrane "A Love Supreme" Anything by Stereolab. Tim Hecker "Harmony in Ultraviolet". late-1960s cool jazz (Miles, Herbie, Freddie Hubbard, etc) Most stuff by Bach. Older stuff by Autechre. Philip Glass "Koyaanisqatsi" - another hour-long track; can't play it too loud though or it gets tiring.

Baroque music generally does it for me. Bach is the exception. When I listen to his more abstract works -- the keyboard partitas, the violin partitas, the well-tempered clavier, the english and french suites, goldberg, the art of the fugue, a musical offering, inventions and sinfonias -- I become so totally absorbed that I just cannot do anything else or even think any other thoughts. Is this what is called /samadhi/?

I usually listen to the di.fm stations, without any strong preference to any one in particular. Some days chillout or ambient works best, while sometimes its goapsy which won't let you out of the zone.

Am I the odd one out in listening to jazz while I code?

djbolivia.ca - he even has a few mixes expressly made for programmers.