The Harry Potter Series is a favorite of mine because it appeals to adults and children alike. It is an escape to a world of make-believe with intricate plot lines.
With my crazy schedule I seldom have time to read for pleasure, but I did mange to finish "Leadership" by Rudy Giuliani. While we are of different political stripes, I did find his ideas on crime prevention very useful.
The Master and Margarita is a brilliant mixture of two modes of discourse that are thought to be antithetical; epic and novelistic. It is also a mixture of genres, time periods and textual strategies that combine a moving love story, scathing social satire and profound re-telling of the story of Christ and Pilate, leading the reader to examine the relative status of "great men" versus common people leading ordinary lives. It is virtually a sacred text for millions of Russians, and with good reason. There is nothing like it in world literature.
My favorite childhood book is Watership Down. It is a story of the relationship between different societies and different governments told in a manner children can relate to.