I don't think the books on this list need any sort of introduction from me, being as they are classics.
Treasure Island, by Robert Louis Stevenson.
The Wind in the Willows, by Kenneth Grahame.
The Hobbit, by J.R.R. Tolkien. In fact, I think it's time to read this again.
D'Aulaires' Book of Greek Myths, and their Book of Norse Myths. Their book on Trolls is fun, too.
The Secret Garden, by Frances Hodgson Burnett.
The Arabian Nights Entertainments, edited by Andrew Lang. Also those color fairy books of his which we've read (we have not yet read all of them).
The Winged Watchman, by Hilda van Stockum.
The Wonder Clock, by Howard Pyle.
The King of Ireland's Son, by Padraic Colum.
A Picturesque Tale of Progress, by Olive Beaupre Miller, in nine volumes.
Peter Pan, by J. M. Barrie.
Charlotte's Web, by E. B. White.
The Princess and the Goblin, and The Princess and Curdie, by George MacDonald.
Pinocchio, by Carlo Collodi.
Scottish Seas, by Doug Jones.
Black Ships before Troy, by Rosemary Sutcliff.
Viking Tales, by Jennie Hall.
Reading this list makes me think of all the good books I haven't yet read to them. Sigh.