Just about anything, although I gravitated more towards adventure novels, horror and SF&F. I went through a bit of a period of reading anything about animals, whether they were anthropomorphised, like in Redwall and its sequels, or slightly (though not much) more naturalistic, such as Duncton Wood, Marshworld or Watership Down, as well.
I would say my absolute favourites were The Hobbit and LotR, The Borrible trilogy by Michael de Larrabeitti, The Deptford Mice trilogy, Whitby Witches and Whitby Child by Robin Jarvis, and anything by Diana Wynne Jones, Ursula K. le Guin, H.P. Lovecraft, Robert E. Howard, Fritz Leiber, Michael Moorcock, Larry Niven, Arthur C. Clarke, Robert Westall, Graham Masterton, M.R. James, Sir Arthur Conan Doyle or Douglas Adams.
Soooooooooooooo many books. Moving our book collections every three years was a larger operation than moving the furniture. It was always the ideal of the other kids "teach the little ones to read really early and you won't have to read TO them" so I read my first novel at 5. (apparently my parents didn't aprove of that book and it was the ONLY time I ever had a book taken away from me.) We had books on every subject under the sun; everyone had different tastes and they were all there for the reading. I think we had more books than the travelling library van.
Books gives me more pleasure than TV ever could. The Brothers Grimm. I read these stories I think when I was four. I was given a big hardcover book full of rhymes for Christmas. It was the Matilda rhyme we had to perform when I was about 6 at school. My most vivid memories of reading are the Thelwell books. With the ponies. I know they're picture books, but did they make me laugh! 
I was going to reget them, but they are so expensive now. I can highly recommend them if you want a good giggle.
