During my ten-day trip to France I heard very little music despite being in a variety of public places. The closest I came to a church concert was in the in the Eglise Des Halles when I heard a street busker as I walked around inside. But without music during the long plane flights to and from France I would have gone absolutely bonkers.
Going from Denver, Colorado to Paris, France took almost twelve hours of flight time and another four hours of connection and being-treated-like-a-terrorist time. During most of that I had my Ultimate Ears Reference Monitor in-ear headphones in my ears and up and running. The Reference Monitors were my one bit of traveling extravagance - I even jettisoned my mechanical watch and extra 160 GB iPod for the trip. And I almost left the Ultimate Ears home, because who in their right mind carries $1000+ headphones on vacation? Me.
I didn't listen to music all the time during the plane flight. During the transatlantic crossing U.S. Air had quite a number of perfectly mediocre "airplane movies" I hadn't seen (for good reason in most cases) that took up eight hours of the flight. The rest of the time I let my iPod 160's shuffle take me wherever it wanted to.
Except for while I'm working out I usually don't spend a lot of time continuously listening through headphones. During the flight was the first time I'd had the Ultimate Ears installed in my head for more than twelve hours at a stretch. Fortunately, they felt as comfortable at the end of the flight as at the beginning, and given the noise level when we first got to Charles De Gaulle airport, I felt no strong urge to remove them once we'd landed.
So, if you want to make traveling, if not painless, at least a lot more tolerable, carry a good, well fitting, set of headphones. Next to Ibuprofen and clean underwear, they're the most important items in my travel kit.