I'm nearly 50 - but my musical tastes probably don't match that demographic at all well (or maybe any demographic).
As a kid growing up, it was rock and some jazz - Beatles, Dylan, Bruebeck from my mom and dad. I still like all that well enough, but it does not define me by any stretch.
In high school the genre of the day was classic rock and disco (which I HATE) and mostly react against these days. Really hate 'hair bands', and 'rock star type' acts.
By college and grad. school - for me music got cool again. I'd say the single greatest influence was Talking Heads: Fear of Music, More Songs About Buildings and Food, etc. I was kinda geeky, and studying Architecture - it just kinda fit. I learned that there was room in the world for everything - no matter how quirky, poly rhythmic, and non-pop oriented. Originality was back in the picture, and imagination and a good idea counted for a lot more than radio play.
After that, my musical tastes were shifted rather permanently away from pop, and towards the fringe.
Artists (old and new) that I'm really in to, and seem to continue in this vein (in their own ways) are: Beck, Flaming Lips, DJ Shadow, Fatboy Slim, Aphex Twin, Beastie Boys, Girl Talk, People Like Us, Messer Chups, Soul Coughing, The Residents, X, The Decemberists, The Brian Jonestown Massacre, etc. Not a definitive list by any stretch - but some favorites that fit the 'rule', so to speak.