The DRM on Kindle ebooks is actually surprisingly easy to crack, and I do so as a matter of principle. I believe in supporting the author and pay for my Kindle library; I also ensure my ebooks can't be taken from me if the company folds/the publisher decides they don't want my money (ie. the 1984 Amazon debacle).
This is actually the reason I own a kindle vs other devices. If I find that I cannot crack the DRM of a book I purchased, that will be the last ebook I buy from amazon.
