I've been thinking about all this, and it occurs to me that there's some stratification even among the personal audio revolution. I'll use my own experience to demonstrate.
I'm 25, so while I would probably be one of the young people involved in the revolution at large, I'm actually slightly too old to be considered part of the iPod Generation. I didn't grow up with a non-physical media personal audio device. I have very fond memories of a portable CD player around the turn of the millennium, and at the time the idea of a handheld device that aggregated my whole music library never even crossed my mind.
I got a 60 GB 5G iPod for Christmas in 2005. It was a revelation. I had already been keeping my library on my computer for years, but my portable listening was still done with a PCDP. I had an enormous collection of CD-Rs (at the end 20+) containing my whole library, but every time I got new music by an artist it ended up separate from the main artist disc(s), and eventually I'd have to redo everything to keep it straight. Sony's ATRAC system cut down on the number of discs, though with cumbersome navigation and poor compression quality as consequences. The iPod was the first device that let me take my entire library with me uncompressed and in a way that allowed for easy navigation, organization, and adding of new music.
In some ways I'm still a member of the previous generation, though. I still buy all my music on physical media whenever I can. It's not because I've convinced myself that I can hear the difference between lossless and any compression format or bitrate*. In fact, I've since embraced compression. It's because I like to be able to control the compression process and use a more efficient codec as it becomes available. VBR AAC is incredibly efficient, in fact; ~175 kbps is transparent to me, as opposed to V0 MP3. I'd never be able to use a Sansa Clip Zip if I had to rely on lossless formats.
I'm also not obsessed with upgrading my portable device every six seconds. That's something that gets joked about a lot and which sets the iPod Generation apart from my slightly earlier one. My iPod lasted me until December last year (seven years, almost to the day), when I finally retired it (it still works and holds a usable charge!). I'll replace my current Clip Zip when it dies. Audio devices don't go "out of date" for me the way they do for the iPod Generation. And I'm not interested in apps or music stores I can access from my device. I just want to play my music and manage my own collection, which is pretty much all PCDPs and computer jukebox software used to do. The idea of a dedicated, manually-organized music-playing device is old-fashioned. Even my Rockboxed Clip Zip can do dozens of things I don't care about.
Going through all this stuff, I think the best way of describing the difference between my generation and the iPod Generation is that the latter regards music devices as a repository for software, and to a certain extent even treats music as software. My generation (a sort of out of band, in-between group) still regards music as a discrete thing, the digital realization of which being arbitrary rather than intrinsic.
*Unbiased, honest testing tells me where my transparency point is with each format.