I would agree with this, except I would put classical music [classicalforums.com] and/or binaural music [blogspot.com] above silence, as both have been shown to improve concentration and reduce learning and recall times.
I'm not sure the binaural thing has been conclusively shown to have a benefit, but I have found that listening to music with binaural beats does make me feel like my mind is clearer and more capable of extended periods of concentration.
Silence would be best, I think, but the problem with the average office is that it is anything but silent, even when it's quiet. There are keyboards clacking, machines humming, cpu fans whirring and air conditioners blowing.
The main thing I'd like to say about this article is that I'm more concerned about what is making workers happy than what makes them a few percentage points more productive.
Everybody is already plenty productive. Too productive, maybe. Our lives are out of balance when it comes to productivity/happiness. Almost everyone I know could stand to be a little less productive and a little more content.