How do you measure the life

My new office neighbor likes to listen to music at his desk. I like it utterly quiet. Now, I already decided on the first day not to say anything to him, because a) he actually keeps it really quiet by anybody else's standards, and b) I have my own office door and I don't mind closing it.

But today, he's listening to the soundtrack to "Rent." And I'm torn! Do I shut my door and concentrate, or do I listen and risk singing along?