I might get a Kindle in time, and like many other people I've grown used to some on-screen reading, even full-length books sometimes, but I agree the casual manual interaction with a paper book, leafing through it, making notes sometimes, building a half-conscious bank of memory of where in a book you saw something, or in what book you saw a given phrase, is part of the experience of reading to me. When reading a book online, even if you're struck by some special part or some particular turns of phrase, it doesn't stick in your memory as to what part of the book it was - not as a "felt memory" (how much of the book you had to the left side, where on the page, etc). When you're reading a paper book, what you read and recall becomes placed within the space of the book, though you won't even notice until you want to find that phrase again. or at least when your mind makes a quick, silent jump back to that recalled bit, that phrase...I'm not talking of hard science textbooks or that kind of thing, which tend to have solid indexes, but more like fiction, journalism, history, travel books and popular books.
Feeling that one's books, and the times I encountered them. read or re-read them, struggled with some of them, form a cloud of definite times and lines in the (well) spacetime continuum of my life, matters to me. It's really personal, and of course it carries back into the lives of other people of the family too - having been given a book as a birthday gift that used to belong to your mother, your uncle, a friend or someone else, or a book with somebody else's handwritten notes scrawled into the margins from a hundred years ago, or a letter or a review cutout tucked inside the cover. Or having talked to mother or grandfather about a book you've read, and which they had read and been impressed by (and perhaps the very same copy!) before you were even born. That kind of thing is really cool, and difficult to reproduce with a library of e-books. Sure, with e-books you can share notes and ideas with other people reading the same book, but even if you would presuppose a time when e-books as a medium will be two hundred years old, will individual copies of e-books (and their "enhanced content" - links, blogs, notes and facebook updates by past readers etc) normally be any more than twenty years old? With standards, reading software and platforms changing all the time, it's a bit hard to imagine that current epub will still be around and readable in any frequent way even sixty years from now.