I have had a Kindle for a couple of years and now I use my iPad for reading books. I LOVE LOVE LOVE them! Right now there are several hundred books on each so I don't ever need to worry about not having something to read. Now I spend a little less than I used to for books, but read far more because of all the free books Amazon offers. Plus I really like the classics and books written in the 1920s and earlier - many of which are available FREE at
Project Gutenberg - free ebooks online download for iPad, Kindle, Nook, Android, iPhone, iPod Touch, Sony Reader . I even get a daily RSS feed from Gutenberg listing all the "new" books made available for download.
I thought I would miss the feel of an actual book, but I don't. I never lose my place, when I run into a new word, I can look it up instantly at the touch of a button, and my overflowing bookshelves are no longer a problem.