As a little addition to the concentration music post, I'd like to mention the situation where there are people talking around you and you can't help listening to what they say and it's very distracting.
Instead of turning up your music really, really loud and ruining your ears, I find that you can tune out individual voices by simply adding more.
This is well outside the realm of "music", but it can be useful. I put it on Youtube several years ago as Talking People Noise. And, to my surprise, has been watched several hundred thousand times. Which certainly isn't stardom, but for a video that's literally noise, not to mention the appalling lack of cute kittens, I'd say it's pretty decent.
Incidentally, the same video can be the solution to a different problem, by making it seem like you're at some social event, rather than sitting alone at your computer. If you care about that sort of thing...