This was a great article on how in this age of Kindle, children's books are still mostly paper:

http://www.nytimes.com/2011/11/21/business/for-their-children-many-e-book-readers-insist-on-paper.html

I tried a few ebooks and apps, especially when Charlie was younger and wasn't as into books. But I prefer paper books... it's just so awesome to sit down together and read a book with your LO.

Do you think that children's books will ever go digital?