Being a cheapskate, I bought a used Sony PRS-300 for $50 that I've been pretty pleased with. The battery charge lasts for weeks, and it's just the size of a thin paperback. There's a Sony bookstore, but the e-reader isn't tied to it. It can read pretty much any e-book format. I'm currently reading a lot of 19th century stuff that I never could find outside of Google Books.

Paula has a Samsung Galaxy Pro tablet that I got her when she was in rehab for her broken ankle back in May. While she can do all kinds of things with it, she mostly uses it as an e-reader, using the Nook app that she downloaded from the Android app store. Amanda has a black and white Nook like yours that she's had for the last year and a half.