I posted the other day about this and linked to an
article I wrote for Teleread on this very topic. I think the article is worth a read because I elaborate a lot on future business models for publishers and how I see the customer experience evolving. But basically, I think it's a mistake to say 'books' as you did and lump everything in together, because there are some types of books which will remain paper, some which will likely not, and it depends on function and use. I may buy a paperback for someone as a gift and buy the ebook for myself. It is not an either/or proposition. But as I explain (among other things) in the article, I think that from the standpoint of retail shelf space, we'll see it given over entirely to children's books, cookbooks, art books and anything not suitable for a paperback-sized screen---plus a print on demand machine for those buying gifts or who prefer paper copies. Anything which is primarily words and does not require pictures, tables and fancy layouts (such as fiction) will either be purchased in ebook or via print on demand machines.