Interesting question. I'm elderly (47)
and I listen to a wide variety of music, including pop, alternative, classical, world, etc. I even watch "That Metal Show" with my DH on Saturday nights (although neither of us are metal heads!) My first date with DH was at a Greatful Dead show in D.C., and I'm a huge fan of The Cure (saw them on their first American tour). I dig Laurie Anderson and I love Kings of Leon and Flaming Lips. I admit, DD and I dance to Gaga in our pajamas. I guess if I hear something that I like, I'll listen and enjoy. I grew up playing classical piano. I loved music from a very early age and I still love music. Music, for me, incompasses many things. Music of my youth has a sentimenal element for me, but I don't feel stuck in my youth.
One of my observations, however, are that many people of my parents' generation (they are in their 70s now) generally gravitate to oldie goldie music. My dad came of age in the era of Nat King Cole. There was a huge cultural divide between my parents' generation and the subsequent kids of the late 50s and early 60s. It seems like human culture was sliced in two right at that point. My mom and dad cannot relate to anything post 50s...unless it is of the Karen Carpenter type music (which tends to be fairly tame and pleasant). For as long as they both shall live, they'll never understand rock and roll (as we know it now) and they have only negative feelings about rap. For me, current pop music or even alternative music is just a progression of what I've always enjoyed or known. There is no cultural jump for me to listen to present music or to appreciate it. If that makes sense.