Read this; the gist:

I have CDs that I have owned for nearly twenty years. I have made back-ups of those CDs. I have converted those CDs into mp3s and more recently into AAC files. I can play them on any device that I want simply by changing the format. If my hard drive dies I still have my CDs. If my portable player dies I still have my CDs. If I decide to run MacOS, Linux, BSD, Windows or any other operating system I will still have my CDs and my CDs will still sound better than the files I downloaded. I have some serious doubts that if music purchased online today will be playable three years from now without breaking the DRM.

He speaks Truth. (More on this issue here — same blog, different author.)