If you like hearing the sounds of nature while you work at your computer, like birdsong tweetings, you could do worse than try the Birdsong Channel (which has temporarily replaced the sorely missed OneWord DAB digital radio and digital TV channel).
It has a Flash player so it should work in modern browsers. And now it's in stereo and broadcast 24 hours a day.
I like Digital One's sense of humour in saying:
"For sponsorship opportunities please contact firstname.lastname@example.org and include the word "Twitcher" in the subject line.
Please note that the line up of birds featured in the cast may change without warning due to illness, weather and migration."
Obviously it uses up bandwidth, but from what I can tell only about 0.01MB a minute, which to me isn't too bad if you're not playing it 24 hours a day 7 days a week. Of course, some employers may block that site, you can only try it and see!
Personally I prefer silence or natural sounds as the predominant ambience in my environment while I work. I generally find background music too distracting even though normally I'm a multi-tasker (when I listen to or make music, I prefer that to be my only or at least primary activity).
Try the Birdsong Channel!