Where I work, we listen to BBC 6 Music (http://www.bbc.co.uk/6music). It's eclectic enough that no-one gets annoyed with the choice of songs (if you don't like one, you'll probably like the next) and there's nothing particularly noisy or distracting on there (loud over-processed pop/dance music, shouty DJs or ads). There's also far less repetition than on similar stations.

I'd much rather this, than one person's choice of "concentrating" music. One man's concentration aid is another man's hell.