I've never been a great bookworm, tended to prefer magazines and manuals rather than fact or fiction books but I was bought a Kindle a few years back and found it useful whilst travelling long aircraft journeys.
Oddly a recent Amazon policy change has altered my reading habits. Most digital books are protected by DRM - this ties you to reading a book on a specific device. As is the norm in the computer world when a company puts a restriction on some nerd discovers a way to get round it. So is the case with Calibre, an ereader management system which is available for Windows, Mac and Linux as well as Android and iOS, and also a portable version for USB sticks.
Amazon recently stopped allowing users to download their books from the Kindle reader to their computers, as a result my interest in Calibre was ignited, it has a great interface, can read, to the best of my knowledge, all various ereader file formats AND remove the DRM, convert the file format and that then allows the user to load an Amazon book on to a kobo reader and kobo books onto a Kindle. There are other readers that I am not too familiar with but I know there are quite a few various eboook file formats.
Due to Amazon's policy change I have ended up over the last 3 months buying 12 books from Kobo, converting them and reading them on my Kindle, my adult daughter is doing likewise though not as many books as me.
The Calibre software is well worth a look if you are an ebook enthusiast.
Geffers
Further to my post there is a project running to offer free digital books to readers, the titles tend to be older classics where copyright has expired.
Apparently 75,000+ books are available for free.
I have downloaded a few to my Kindle and formatting seems fine.
Geffers