Right before William's sixteenth birthday he gave written answers to questions from the press, though I dont have the exact answers here is what William basically said.
William's likes: Eton College, Eton's uniform (he really doesn't mind it), writing letters, calling family and friends, and going to action films at the movies
William's dislikes: being a pin-up and dealing with female teenage adulation
William's favorite sports: rugby, football (soccer), swimming, water polo, tennis
William's favorite books: action-adventure fiction and non-fiction
William's favorite clothes: modern style and can shop for himself
William's favorite music: techno (dance) and some classical
William's favorite band: couldn't say
William's best friends at Eton: couldn't say
William's favorite food: simple dishes and junk food
William's ambitions: to go on safari in Africa, like Harry and his dad did last year
William dislikes: enjoying computer games, but not having a computer of his own
William's pet: Widgeon, a female black Lab, likes horses