I love to read so it's difficult to choose just one favorite book...
When I was young I loved: The Secret Garden, Where the Red Fern Grows and A Tree Grows in Brooklyn
When I was in college my favorites were: The Jungle, I Know Why the Caged Bird Sings and Fear and Loathing in Las Vegas
The best books I've read in the past 10 years are: Push, The Help, Little Bee and any short stories by David Sedaris (very funny)