I'm one who likes a wide variety of music, so I'm thinking this might be better for me. Plus, the whole ownership thing doesn't appeal to me any more. For example, I have 200 DVD's I never watch any more, about 100 books I never read any more, and a couple thousand mp3 songs that I probably listen to about 20-30% of even rarely.
Maybe odd, but a combination of the two might be best; by paying to sample whatever I want and purchasing what I really like. Kind of like a digital camera where you can take tons of pics and only print the pics that come out good. The rental end may make the whole thing cost more, but in the end there would be less wasted money on music I don't like; which is why I'm always hesitant of purchasing music to begin with.
I know Ipod can't be used with subscription, but there are tons of other players that can, right? What kind of music is not available; like most popular or non-mainstream stuff? I heard some rumors flying around that Jobs was considering a subscription plan, but I don't see that happening. He'd really be stepping on himself after everything he's said against it. In the end, music is entertainment, just like movies and TV shows, and they very successful in renting.