Even with millions of astronomy and space images freely available on line, I still like books, and I have tons of them on space and astronomy and many other subjects. Old habits die hard I guess. I sometimes also give away books as raffle prizes at educational outreach events, so I'm always looking for good quality, low cost astronomy books to use for this (and to add to my own overcrowded shelves).
One series I really like is from UK publisher Quercus, Earth and Universe by Nicolas Cheetham and a third one I found just last week, The Planets by Giles Sparrow (the Amazon links are for hardcovers for $15 to $19 - I've found the paperback versions for $5.99 on the discount tables at Borders and Waldenbooks). They are basically all photos with brief text captions for each one. They are large format books and the color print quality is good. If you want to start or add to a low-cost astronomy library for yourself or your kids, you can't go wrong with these.