In junior high and early high school I listened to punk and metal, because I was a dumn angry teeny bopper. Bands like Bad Religion, Slayer, RATM, The Clash, Rancid, etc. I was also, and still am, a huge Primus fan. Hearing Les Claypool was my divine calling to pick up a bass at age 12.
From later high school to college/current I started appreciating more diverse kinds of music. After getting over most of my prejudices towards "hippy" music (something a lot of people on this board should do), A guy from work introduced to the Grateful Dead and Widespread Panic. Listening to them helped me learn to appreciate more "roots" music, like early Jazz, Blues, Folk, early Rock n' Roll and even some Classical.
A recent fetish of mine is Bluegrass.