From the opinions of a 14-year-old:
Listening to this conversation is really interesting. No one can define a winning argument because everyone's opinion of what is good music is different. For me, I love electronic with the occasional rock or classical thrown in the mix. I can't stand screamo or heavy metal only for the reason that it all sounds the same, but I respect that lots of people do like it. My friends think that my electronic music all sounds the same as well but don't tease me because I do not like their favorite music.
Each to his/her own.
As for the age factor, music will never die. People will always have fits of nostalgia wanting a renaissance of a certain music style. It will always happen. What you do then is listen to the music you like and wait for a revival band to show up (it happens).
On the subject of today's musical genres:
~Pop~
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I said I liked electronic, but the pop of today's world is too shallow for me and too washed out. This is most prominant with Disney. Almost every girl actor is turned into a pop sensation. I respect that people like Raven, Hannah Montana, Hilary Duff, Aly and AJ, and the Cheetah Girls. I just don't like them personally.
~Rock~
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I like gentle rock, ballad, or alternative (the moderate definition). I like people like Switchfoot because the songs normally have a positive edge without the gratuitous sex or drugs. Maroon 5, although it does have the gratuitous sex and drugs, is still on the mild side and a personal favorite of mine. My tastes are not exactly up to par with everyone elses, I'm sure, but it satisfies me.
~Heavy Metal/Screamo~
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As I said, I do not like this style of music (it gives me a headache). But I will try to listen to it when a friend asks me to and when they ask if I liked it or not I say, "It was okay, but it's just not my style of music." Enough said.
~Hip-Hop/Rap~
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There have been good arguments on this one. I will not listen to hip-hop or rap (despite it's extremely close relationship with electronic music). The only hip-hop song on my iPod is the Cha Cha Slide. However, I hear it on the radio a lot and I'll tolerate it. Lot's of people sing it in my igh School's hallway so I know a lot of the songs. It's just not my type.
I think I touched on a little of everything. This is just the opinion of a 14-year-old.