I have to add my support for the Sony Reader - I'm a newbie with the dedicated eReaders I used a Palm LifeDrive and paper books before I got hte 505 a few days ago. I'm an avid reader, I read everywhere, and never go anywhere without a book in my purse. As grimo1re said, I also read when brushing teeth etc etc.
The 505 is a nice size, I've easily bought books from Fictionwise either directly in the Sony format or easily converted with Calibre (including secured books), so getting books for the 505 has not been a problem so far. I have 183 books/magazines on there now, scifi and novels. I'm soooooo happy to be able to go anywhere and not risk being without a book to read. The 505 turns on quickly and is easily put in 'pase/suspend' mode with the sliding switch on top, so it's easy to read even with just half a minute to spare lol
I would recommend getting the lighted cover, with built in lightwedge. I used to read in bed wiht the Palm handheld on a low light setting, so I really do dislike reading with the 505 using a separate reading light clipon, and the nightstand lamp disturbs hubby and kid. So the lighted cover is essential IMO for someone that reads everywhere. And I *imagine* that it gives some added protection for the screen?
Pdf-documents: I have put pdf-format manuals on the reader, and they look decent in most cases. Fine for what I use them for, i.e. look somethig up when needed, not for reading from beginning to end. But I have several old pdf-files that I haven't looked at yet or tried to convert, because i think it might be a problem since they are not text but images - I was on sick leave a few months and scanned most of my manuals/handbooks for my hobby but as images not text.....

But I gather that is not something your wife will need anyhow, so it's not an issue.