What is that X-Factor that makes a children's book stand up to the test of time? I think the stories need to be realistic in the sense that a child can relate to the characters and the situations. The situations should be familiar from one generation to another. Illustrations always seem to be better when they are hand-drawn, instead of computer-generated.
Books that are read to a child at a young age are going to stick with her for the rest of her life. Different books are going to speak to different children. So, when you find ones that work, read them again and again so that they are passed on.
I think it is also important for the book to be in physical form. You get more out of a book when you can engage most of your senses. There is something to be said for feeling the smooth pages of a new book. There is something about that new book smell. You have less eye strain when you're looking at a piece of paper instead of a backlit screen. And it is easier to snuggle when paging through a book than pushing on a touch screen.
What are some of your favorite books? What was that "X-Factor" that helped it to make your list?