DS (3.75) loved all the above, especially Magic Tree House, Magic School bus, Faraway Tree and Wishing Chair series, Frog and Toad, Paddington. He is now reading Puppy Place books (all very tame as he is sensitive to anything scary) and Pet Vet books. He still loves more in-depth picture books as well as non-fiction++. Non-fiction are great as you don't need to worry so much about the content smile. He started with the Usborne Beginner series eg space, castles etc but now reads anything.