I bought my Kindle because I was going to live in Norway for a year. I knew I'd be reading a lot as I traveled all year via plane, train, bus, ferry, and subway. I didn't see the point of lugging heavy books all over the world, so I thought a Kindle would be a good purchase. It went everywhere with me. I always had something to read, and it was relatively light to travel with.
In the last year that I've been back in California, I haven't really used my Kindle. I haven't traveled nearly as much, and when I have, I've toted more academic books with me so that I could work. I've also bought a couple of hardback books (which I now regret).
BUT . . . over the last few weeks, I've been sorting through all my things, and I've realized that I have way too much stuff . . . including books that I read once and never look at again. I'm starting a pile of things to get rid of, to make room in my house to organize and to get rid of clutter. As I've sorted through my books, I've realized that I needed to break out my Kindle again. I love crime fiction, but, except for Tana French's In the Woods, which I taught fall semester, I don't see ever repeat reading specific novels. Even Michael Ondaatje's Divasdero, a book that I adored, is not a book I need possess in tangible form. My pleasure at reading that book is about the content, the story, not the feel of the book.
I've started using my Kindle again. I don't think reading devices are the death of books (unless by "books" you mean the physical artifact, not the content--and even that is debatable). In fact, my Kindle allows me to read and own more "books." I can revisit them should I ever care to, and there are certainly still some types of books that I prefer to own in hardback (poetry, anything by Alice Munro, books that I might teach some day).
So . . . save a tree, make more room in your home, be an avid reader. Buy a Kindle.