My iPod is an emotion outlet for me. At the tables, music can bring me to the light or turn me to the dark side. When my luck is down, I turn up the blues. When I'm on a roll, it's "Eye of the Tiger" time. I listen to music to calm me, pump me up, or bring my mind out of the game just enough to avoid tilt, bankruptcy, and bloodshed.
Tunes are not always a welcome distraction. Short-handed, I take the head phones off just for the high-frequency of decision making. This is when your mind needs to be in the game to catch every tell and analyze every move. But for the long game, your brain needs a break. Use music to unwind from time to time. Practicing this will keep you sane and save your heightened focus for when you need it most.
When it is most important to unwind is after the inevitable bad beat. For me, nothing extinguishes my burning rage like a little Bob Marley, but find what is right for you.
Alternatively, the right playlist can strengthen your resolve and restore the will to play aggressive once more! The strength of music is that is provides the theme to different playing styles--prompting you to mix up your play, which is essential.
Note: I will be posting the songs I use most at the poker table at a later time.