I definitely wish there was an iTunes for Linux. As I have been going along and trying to learn more and more songs on guitar, I have noticed I don't have some songs that I'd like to learn. It's difficult to learn a song without being able to listen to it a few times, even if I know the song well. So, it would be very nice to be able to go to something like the iTunes Music Store and buy the song for $0.99 and be able to learn it. If I have to buy the whole CD, it's a pain in the neck, especially if I just want one song.
What I don't understand is why Apple doesn't just do the port? It would really just be a GUI port, as OS X is based on Unix. How bad is the conversion from Cocoa to something like a GTK or a QT? It would be a big win for Apple, as they would very quickly get a lot of Linux users like myself to pay $30 or $40 for the software and then be able to start buying music. Supposedly they are doing a Windows port, but I think a Linux port (hell, even things like FreeBSD, Solaris, etc etc could have ports, its just a GUI port) would be quick and get more people using the service much more quickly than porting to Windows.
Update:
More evidence no one selling MP3s likes Linux:
Thank you for visiting BuyMusic.com.In order to take full advantage of BuyMusic.com's offerings you must be on a Windows Operating System using Internet Explorer version 5.0 or higher.
Doh!