Can you work hard while listening to music?

Could we please hear your recommendations for music that wouldn't ruin your productivity or concentration at work?

My general happiness in life is so improved by music that I would like to put a stereo in my office -- but some of my work can be very technical and I don't want to be too absorbed or distracted.

Of course, I am not talking about "elevator music" -- just trying to identify things (not just classical) that are rich and worthy of repeated listening/study, yet perhaps also have a soothing or meditative quality.

Perhaps this is extremely personal and also varies greatly depending on ones profession -- but if something works for you, perhaps you could remind us of what you do to pay for all of your expensive audio gear.

Thank you.