I love my Kindle, even though I am on my 2nd as the first broke! Thankfully Amazon claimed it was still under the 12 month warranty even though I'd had it for about 18 months, so they sent me a new one free of charge.... result!
When I first bought my Kindle I did pay to download books, purely for those I would have bought in hard copy anyway. But these days I just tend to download the free ones from Amazon. I have also bought a couple of dvd/cd roms from eBay, one of which had 11,000 books on it and the other a few hundred... paid about £3 for each disc and am able to replace about half of my hard copy library from the 2 discs! OK, granted, there are lots of books on each disc I am not really interested in reading but I've had way over my money's worth from each disc for those I do want to read!