I would prefer an E-book. I foresee that it would become cheaper, more content can be stored with much less space, and (copyright aside) the contents of the book can be more easily replicated and preserved and it will much cheaper and efficient to produce books. E-books may be a niche product, but I anticipate it becoming more prevalent. Or even if that is not case, books will most likely be written and presented in digital form.
I personally wish that I can have a database of newspapers and books. However, having a library of those take too much space. Of course, if I had a favourite book I would like it hardcopy. But not all books are to my liking. And if it were the case, I would have them in digital form or in an E-book.
I am not entirely sure if I can print an E-book (i.e. print out the contents of an E-book), but if this were the case, I could have the best of both worlds, with print and digital material on hand.
Long short story, the digital medium is really convenient.