I have way too much in the un-read area of my e-book readers ( I read on my iPad using iBooks, Kindle, and Readmill ). I've had the Kindle app since it first was released on iPad, but I don't keep all my books downloaded (to save a bit of space). I have a lot of books in the "cloud". Most of these, I probably won't read. Most are free or public domain books so deleting them won't be a big deal.
I like the [Readmill](http://readmill.com/) app. It feels more like an RSS reader. That's a good thing for me. I feel like I'm just reading long form articles; 10 pages instead of 200. I feel like I can finish reading. No pressure. The app also times my pace and let's me know how much longer before I finish reading. I finished reading Cory Doctorow's [I, Robot](http://readmill.com/books/i-robot) short story on Readmill and fell in love with the author. I've queued up once of his other books, [Makers](http://readmill.com/books/makers). It's a free ePub book.
Although I have a few books in Kindle format I've decided to stop purchasing books through Amazon. Although most e-book sellers use some form of DRM, Amazon.com, uses a proprietary book format. iBooks, Readmill and others uses the [ePub](http://idpf.org/epub) standard. I can import DRM free ePub books into iBooks or Readmill or Kobo but not into Kindle. I would have to go to Amazon.com and get the Kindle version of the book. I've started purchasing DRM-free ePub formated books from [feedbooks](http://www.feedbooks.com/). [Kobo](http://www.kobobooks.com/free_ebooks) also has a lot of free ebooks.
So here's my reading lists in my various eReaders.