Also, wrt. headphones, in addition to potential hearing loss, it's painful to wear them all day long, they don't block out all sound, and a lot of people don't respect the headphone rule.

That said, when I'm in the type of environment where I need to wear headphones, I think brown noise (e.g., from sox) is a nice alternative to music, and white or pink noise behind music helps create a consistent sound screen.

Here's my brown noise script for sox (it's supposed to sound a little like waves):

    #!/bin/bash
    play -q -c 2 -n synth brownnoise band -n 1600 1500 tremolo .1 30