I liked horse books when I was young, which is funny because I'm no fan of horses now. But no other animal books. I could never get into Watership Down, and in fact I now have a 'no books written from the POV of animals' rule, which I have broken only for Terry Pratchett.

I liked the Swallows and Amazons series by Arthur Ransome, and loads of Enid Blyton, the Earthsea trilogy, The Hobbit and the Chronicles of Narnia.