Others have posted most of the books I'd name. A few others:

The Phantom Tollbooth - Norton Juster
The Glass Slipper - Eleanor Farjeon
Bambi - Felix Salten
Edward Lear's nonsense books
The Good Master and The Singing Tree - Kate Seredy
The Oz books - Frank Baum
The Little Prince - Antoine de St. Exupery
The Gnu and the Guru Go Behind the Beyond - Peggy Clifford
One Hundred and One Dalmatians - Dodie Smith
Anything by the D'Aulaires, especially their Book of Greek Myths
Paddle-to-the-Sea - Holling C. Holling
Where the Sidewalk Ends and The ABZ Book - Shel Silverstein
Anything by Mercer Mayer or Leo & Diane Dillon
The Pied Piper of Hamlin