It's interesting to look at the offerings for e-readers now, a couple of years after they have gained a mass audience. It is only since Christmas 2009 that there has been significant demand for e-books at the library. Before that, our digital downloads from NetLibrary and OverDrive were focused on audio books.
Two years ago, e-readers were not connected devices, and had to be loaded with e-books that had been downloaded to a computer. Now they are all wireless, though they still have USB ports. I had hoped to find one with a large display, approaching the size of a page in an octavo book, but of the Sony, Nook, and Kindle e-readers, only the pricey Kindle DX, with its 9.7" screen, meets this requirement. The 6" screen is common, but I'm concerned that PDF's of out-of-print, copyright-expired books from libraries, of which I have many on my PC, will be hard to read on them.
I am not willing to go with a Kindle because they do not handle the EPUB format. The Sony PRS-T1 seems to work best with PDF's, with a pinch-zooming feature, but I'm not sure this is good enough.
I've been reading the reviews at The e-Book Reader.com. The video reviews have helped me understand how e-readers work. And he says, reviewing the Sony, "If you want a hardcore, everyday PDF reader I would suggest getting a tablet", something I was beginning to think on my own. Then, what is the e-ink display worth to me? I have done plenty of PDF reading on PC's. I just wish I could read PDF books in a comfortable chair. So, maybe a tablet?