I lost my original headphones a while back and didn't like the idea of getting an adapter. The part number for the headphones is SYN9870A (thanks maxx_730). There were none on eBay when I checked, so I got mine from here:

http://www.ustronics.com/moonetohesy.html

About $15 after shipping, and the headphones I got were black instead of the original grey I had, and I think these look a lot better.

Just an FYI if you need new headphones.