Noise cancelling headphones make the commute bearable, so I can block out the nattering women who always seem to sit near me on the 06.39. I inherited a pair of Bose noise cancelling phones, and though they may not be the last word in hi-fidelity they do a damn good job of cutting out external noise, and they're v comfortable too.
Also blocks out the cretins blasting out rap stuff on their ipods (those standard ipod
d headphones are useless, everyone else in the carriage hears everything they're listening to).