Very interesting - I don't know about rock music.

I got an extensive collection of new age, jazz, international language music and the oldies - practically all my CD collection are in two classic Ipods which I use everyday during my long walk(sort of not walking and not jogging but in-between) in the morning.

Recently I added movie "soundtracks" into my collection, I prefer the melodic and instrumentals.

Will keep your IR bookmark - will explore one day.