Within few days of official release of Harry Potter book an online version is available to download aka eBook.
Both forms of have their own pros and cons. I prefer IT books in ebooks format, because it allows me to do copy past of code or command or even I can search it for particular command or topic. eBooks also gives an opportunity to normal people to publish book (self-publish) which can cross the boundaries very easily. If you are student then ebook is your best friend to save money. These days many universities provides the ebooks to students. You can take printout or carry the ebooks in portable device read it anywhere anytime. No more bookshelf. One think I don’t like about ebooks is its quality in terms of printing as compare to my computers digital screen. Smooth nice white paper with fine picture and printing quality also gives fine reading pleasure.
However, when it comes to collectors items then you I always prefer paper books. It gives best reading experience. Imagine hot cup of coffee and Sunday afternoon in bed with nice paper book, oh boy what else man want? To be frank when I was kid my grandpa everyday forced me to read newspaper and especially cartoons. Later I grown up with lots of story and other books gifted by my dad and mom. In short paper books gives an elite reading experience.
It is better not depend too much on technology as far as books are concerned :)