Do you have a local library that has free e-books for checkout using the 'Overdrive' service?
Overdrive now uses mainly EPUB formated books with Adobe DRM to enforce the checkout time limits and protect the copyrighted materials.
The Nooks, Sonys, and most other e-book readers handle this seamlessly.
The Kindles don't handle it at all (though some get around this by stripping off the DRM and converting to a format that Kindles can read).
I REALLY like my local libraries Overdrive services, and having quick easy access to those services without having to skirt the law is important to me, so the Kindle simply wasn't an option.
Through Overdrive I have access to almost 700 EPUB e-book titles available for free download. Like any library book, you may have to put in a request to reserve a popular title, but you can do that right from the web, and be automatically notified when the title becomes available.
If you don't want to wait, you can also direct the Overdrive advanced search to only show titles that are currently available . I have stumbled onto some wonderful titles from authors that I had never read before. Remember, the thing about librarians is that they KNOW BOOKS. Nothing better than surfing through Overdrives electronic shelves and stumbling onto a hidden treasure.