EDIT: Thanks for all the suggestions!
EDIT: Thanks for all the suggestions!
And of course there's Aphex Twin's Selected Ambient Works 85-92, which should go without saying really. Again, you might not be able to work because it's such a good record. Also, it's not ambient in the sense of having no beats. If you've never heard it before you should probably just stop working right now and listen to it. Also he did a SAW vol. 2 album which is more beatless, but it's not as good.
You can't go wrong with Future Sound of London. It's a bit dystopian, but utterly amazing stuff.
The "minimalist" (he hates that word) work of composer Steve Reich is also very good for zoning out. All the other people in the modern "ambient" genre are ripping him off to some extent or another. I suggest starting with Electric Counterpoint.
EDIT - some more:
Hecq - 0000
Almost anything by The Orb, especially The Orb's Adventures Beyond the Ultraworld. Make sure you get the proper UK version not the cut down US release.
Portico Quartet by Portico Quartet
All the Boards of Canada stuff
Also I'm a big fan of M83 Digital Shades Vol 1 for this purpose.
Personally I don't believe it for a second.
http://www.gearslutz.com/board/electronic-music-instruments-...
To be fair he could have written that stuff as a teenager. But then maybe he also owns one of Kraftwerk's original vocoders, modified to produce output in Cornish.
Apparently he also has a lookalike that walks around at his shows to divert the attention of fans.
Etc etc.
I've bundled them together in a Grooveshark playlist: http://grooveshark.com/#!/playlist/Work+Ambient/87531575
Listening to it again now. Classic. Here they are in full effect back when that album was recorded. The CGI is all them as well. It's all very demoscene. https://www.youtube.com/watch?v=__tAx6-Fo6g
Those were the days. And to be fair looking at tumblr now, they've kinda made good on their promise.
http://www.last.fm/music/Carbon+Based+Lifeforms
http://www.last.fm/music/H.U.V.A.+Network
Other artists on Ultimae are also worth a try.
I'm terrible at music genres myself, but I am a huge fan of Bonobo's music. It's classified as trip-hop - no idea if that falls under this category. Bonobo - Black Sands http://www.youtube.com/watch?v=cTjF2_-bneM the entire album is amazing
He just released a new album not long ago: http://www.youtube.com/watch?v=62Z4ibZFA6c&list=PLXEYOK9pTAB...
I also picked up a Grooveshark playlist from someone (but can't rememeber where I got it from) that works really well: http://grooveshark.com/#!/playlist/Ambient/54561881
Also of interest is StilllStream, an ambient radio station: http://stillstream.com/
Billow Observatory - Billow Observatory
Nuojuva - Valot Kaukaa
Global Underground 24/7 - Danny Howells (Day Disc)
Willits + Sakamoto - Ancient Future
Nils Frahm - Felt
Bersarin Quartet - II
The World on Higher Downs - Land Patterns
Helios (Keith Kenniff, aka Goldmund) - Caesura
Trip-hop.
About 60 album length mixes