Does something like Pandora exist with just Instrumentals?
Classical tends to draw my attention too much, as the good stuff is really complex and deep, and will pull me right out of flow when it gets to the tricky parts. Same problem with Jazz.
Most "easy listening" music makes me want to puke and throw things or stab someone, so I just don't go there.
* The Missing http://www.youtube.com/watch?v=0gzXpzDwwbI vocals don't bother me.
* Hizbollah http://www.youtube.com/watch?v=0JRxVov_0a0 has vocals I can't understand ;-)
(For example, the "cliqhop/idm" shoutcast stream is what I use when I need non-distracting music in the background, for working.)
I strongly recommend some Finnish songs. They have powerful voices and pretty strong instruments with roots to classical styles, but with a metal twist. It might be your cup of tea as well.
The point is, do not necessarily avoid human voice as long as it's not your primary language.
Clickable: http://www.macksearplugs.com/details/ear-plugs-for-loud-musi...
I use them when flying, or working in a common space. Worth buying in bulk and keeping. They can stay in comfortably on a 13 hour flight without impairing your ability to hear someone approaching/speaking to you.
* Neoclassical (Arcana, Ophelia's Dream)
* Post-Rock (God Is an Astronaut, Explosions in the Sky, Mono)
* Shoegaze / Dream Pop (Beach House, Cocteau Twins)
* Nu-Jazz (Parov Stelar, The Kilimanjaro Darkjazz Essamble)
* Dark Ambient (Lustmord, Desiderii Marginis, Sephiroth)
I've been on a dusbstep kick lately. Heavy bass and fast beats tend to be great for getting into a groove and coding like a maniac.
http://feeds.feedburner.com/EdBangerRecords
no vocals (or very little), never enough to distract.