Comment If you must stop, buy some good earplugs (Score 1) 1019
For about 6 months, I sat in a cubicle that faced a sales guy. As part of his job, he was on the phone about 6 hours a day, talking right at me.
My solution in the end was to go to a hardware store and buy some construction grade ear protection - the over the head, earmuff style that you see on people operating jackhammers. Cost me about 20 bucks, and almost completely drowned out everything around me. (They are about as good in an office setting as the bose noise cancelling headphones, and about 90% cheaper)
It also sends a clear message to those around you. When I had headphones on, people thought I was listening to music for enjoyment. When you put these things on, it sends a very clear STFU, I'm trying to think, message. (OK, it did feel a little juvenile, but after a few days, it was fine. People understood that I didn't hate them, I just needed some quiet, and this was the easiest way to accomplish it without sssh-ing everyone around me.)
As an alternative, I've actually found that even just having headphones on, but no music playing (assuming large, over the ear kind) is pretty effective as well. It drowns out some of the noise, and has the added benefit that people assume you can't hear them, so they don't talk to you. I actually spend about half of my day with earphones on that aren't playing a sound. When I'm doing something easy, I turn on the tunes, when I have to think, I turn them off but leave the headphones on.
If you spent the next week with the headphones on, but the cord clearly lying on your desk, unplugged, I think that might help your boss understand that the phones are not what he thinks they are for.