Thanks to things like Spotify, I don’t really need to have a huge library of songs constantly on my computer. So, host my library on the Windows partition, then keep a smaller one/use spotify for when I’m in Mac OS X. I get to use the Zune HD and my preferred OS.
Who'da thunk I'd have two posts in the same morning about a gizmo I've never even seen?
But, reading just the short excerpt above, you can see what a Tower of Babel all this is for a typical user. A separate operating system just or music? Granted, that's what a Mac user (like me, now) would have to face if they want to use a Zune.
But the point is, if the content is "in the cloud," then it shouldn't (ultimately) matter what platform, device, or operating system you're using.
And again with the Spotify? I have no idea how well Spotify the service actually works, but I'll tell you what does work: Spotify's PR department. I've never seen so much hype for a service that your typical user can't even use.
Point taken, though, re: iTunes. That remains a closed eco-system, and some of its particulars are getting pretty stale.