I love the Sneetches. It has such a wonderful message about ending discrimination, peer pressure...tons of profound topics dealt with in goofy Dr. Seuss style.
My all time favorite Dr. Seuss book is "The Lorax." The message about protecting the planet is awesome. We've read it so many times, that our 10 year old can recite the Lorax speak ("I am the Lorax, I speak for the trees. I speak for trees for the trees have no tongues......) She was very disappointed when she didn't get a Brown Bar-ba-loot and a pink Truffula Tree on her 4th Birthday!