Aside from the changes in how music is delivered, as mentioned above, it seems to me there is a consistent move back in time. Songs being remade or reworked--often even by the original artist--has become a popular form of current music. I guess I should be thankful, 'cause I seem pretty "hip" and "cool" when I know some of the latest songs. They don't have to know I simply remember the songs from high school.
How about youtube? Music (in addition to other things, of course) and musicians have springboarded from obscurity into stardom through this venue. I've also noticed a huge trend of making parodies of popular works. Sure makes it easier for an English teacher to teach parody!
In terms of recording, the trend is to record everything loud. There's no highs and lows, only highs. No stereo anymore. No subtlety. It's all designed for MP3 or iPod-style playback, directly into the ear. Music is not designed for a large room any more.
I think that we will see a trend of going back to "real" music as ask996 eluded to in her above post. I also agree that the talent level is not what it use to be. However in today's world of being able to manipulate sounds it doesn't have to be.
I would certainly agree that gimmicks seem to be driving many of the music performers today. There is no doubt that earlier generations had their gimmicks. Look at Kiss or Alice Cooper. However, it seems as if they made more original music with regard to lyrics and instrumentals. Much of today’s music is synthesized and I miss “real” music.
I've noticed that the concerts in my area are prohibitively expensive. Perhaps this is a result of all the downloads and loss of revenue from copyrights. Experiencing a live performance far surpasses listening to recorded music. The atmosphere of the audience and the venue can add a lot. Unfortunately, many people will not be able to experience this personal appearance of a talented performer.
As far as actual genres go I would say that it depends on where you live and what age group you are in. As a teacher I have also noticed that many teenagers today are really liking classic rock.
In addition to the first posts, teens (as well as adults) really like downloadable music. It is quick, easy and convenient. You can store everything right on your computer. It makes life much easier.
Post #1 has raised an important issue regarding the music industry. Apparently, hope has not yet been abandoned by the many musicians facing the illegal copying of their music. To compensate for the loss in revenue derived from royalties, many musicians have increased live concert performances and merchandise to their activities. This trend has derived from necessity.
One trend in the industry is the move away from CD's and "physical" music. So much more is being sold as downloads now, and copyright is almost impossible to enforce, and the artist is getting a shrinking share of the revenues. It has already forced many artists out of the business or to sell their own songs online.
Popular trends seem to focus more on appearance and originality than on actual singing talent. One thing that is growing is the categories of rap and non-vocal performances. It is becoming clear that it is more about how one packages themselves as opposed to having musical talent, something which is in every field of society.