The thing about DRM is that there are always exceptions to the rules-- while Apple has released lots of DRM-free music, lots of it is still bogged down by DRM, and if you're like me, you disagree that any music you purchase should be limited in the ways that you use it.
Fortunately, as long as you can hear the music you buy, there'll always be a simple way around the DRM, and 5thirtyone has put together this simple writeup explaining how to break iTunes DRM with a tool you've already got on your Mac: iMovie. Essentially, you load the DRM-ed file as a soundtrack in iMovie, export it as an .aiff file back into iTunes, and then convert it in iTunes back to AAC. Simple enough.
This makes you question why DRM is there in the first place. Sure, the record companies might be pushing it on Apple, but if it's this easy and simple to do, exactly what leg are they standing on to justify it in the first place?