When iTunes Music Store first came out I studied it and decided to buy music off it. Not because I trusted Apple, but because I had a spare Mac that I could use as a DRM lifeboat.
I copied my purchases as I made them to the old Mac. The Mac was also disconnected from the Internet after its initial authorization. Finally, I had software in place to extract the audio I purchased even if Apple pulled the DRM football from me just as I tried to kick it.
Fortunately Apple’s iTMS DRM dog never barked. But after today’s Amazon Ebook controversy I decided it’s time to share my similar Amazon Ebook Insurance Policy:
Have the Kindle’s network turned off most of the time. I do this to conserve battery on my Kindle 3, but it has the nice side-effect that Amazon can’t remotely delete content at its whim.
Buy Chronosync and set it up to copy purchased Ebooks to my Mac whenever I connect+charge my Kindle. That way I can recover even from an unexpected remote wipe from Amazon.
Use (and hopefully donate to) Calibre and then install plugins to strip Amazon’s DRM from your purchased Ebook files. Calibre can then export your .azw and .azw1 files to unencumbered .mobi and .epub formats.