Re: subscription
I think there is at least one good reason for Apple to adopt a subscription model option for iTunes, and that is college kids. Many colleges have struck up arrangements with subscription-style services in an effort to discourage old-style Napster stealing over college networks (which the schools could theoretically be liable for).
At some colleges (like Penn State) the school actually pays the monthly fee for the students out of the student activity fees. Good deal for (new) Napster, (who I think they use) and okay deal for PC-using students, but it's a stinker for Mac users, who are forced to pay for this through their fees but can't use a PC-only service. And I can tell you from personal experience, neither administration nor IT gives a rats ass about this situation.
But if there were a Mac-compatible subscription service, then it seems like they'd be hard-pressed not to offer it to Mac users on the same free basis as Napster. In fact, if it were competitive in cost, Apple could probably pretty much take this market, given their mind-share in digital music.
Smarter folks than I would have to figure out the details...but then, Steve's a pretty smart guy.