But there are still many iTunes holdouts.
AC/DC, Kid Rock, and Garth Brooks are just a few of the iconic, influential artists who have kept their music from Apple's iTunes, some calling it Apple's application a "monster" that will "kill music."
We've compiled some of the biggest iTunes holdouts in the slideshow below (part of which originally appeared here).
Are there other musicians you've been missing from iTunes that we should add to the list? Click "Add a Slide" below to include them.