I'm interested in the back and forth between the Boston Unitarian and Southern "Universalist Church" History blogs about what Universalist works are available for the former's Nook, the book reader released by Barnes and Noble.
I confess, that if pressed to own a book reader, I'd probably get the Nook: it's a better value than its competitors, and is fundamentally an Android device, like my phone. As such, developers have found ways to add additional software to it, like a media player or a web browser. (But I'm not in the market and I can read books on my phone, if pressed.)
I'll get to the titles later; indeed, I hope to dust off some old work and republish it in a format most book readers can accept. And so the biggest reason I'd choose the Nook (or Sony's Reader) over an Amazon Kindle is over what files it accepts. I'm becoming more fond of the EPUB standard. (If the subject interests you, also read Joe Clark's breakdown of the HTML-ness of EPUB.)
If you care about books, should consider your rights as a reader, since "Digital Rights Management" -- now perishing in recorded music -- is booming in electronic books. An encumbered electronic book does not give you the same rights to share or store as you have with one made of paper. This is not inconsequential for those who hold on to books for decades.
For background on the matters, see the Electronic Frontiers Foundation's Digital Books and Your Rights. (Also available there as a PDF: some book readers take that!) Or, if you like something with more punch, check out the Free Software Foundation's Defective by Design site. (This page about the Kindle.)