My 13 year old is also living with ear buds in her ear. But what blew me away was what she was listening to - "Afternoon Delight"...and actually liking it. My God I liked that tune when I was 15 years old! She also likes Queen. But then she'll do an 180 degree turn and be listening to the Gorillas (surprisingly I like them too).
My 9 year old, on the other hand, likes Crazy Frog and the Notorious Cherry Bombs. But that's my husband's fault.