When I was younger I nearly always did my yoga practice to music. Whilst I am a rock music fan, obviously I used to choose something a bit quieter for my practice -- some Wah! some buddhist chants, some Shiva Rhea. These days, however, I find it really distracting to listen to music while I'm practicing.
I'm not sure why. It could be that my practice has changed so much -- from Astanga Vinyasa to a gentle meditative Viniyoga practice, that because rather than doing a set routine of postures I am listening to what my body wants and needs each day and in order to listen I need silence. It could be that as I have worked deeper and deeper into my yoga practice I no longer feel the silence around me oppressive, I no longer feel the silence to be a void that needs filling with sound, but instead welcome it on to my mat with me.
On the other hand, I studied for my A Levels listening to Jane's Addiction and New Model Army very very loud - now I can't even reply to an email if there are any distractions so it could just be a simple matter of getting older!