I judge my favorites by whether or not I'd be willing to go back and read them again. The ones I've read the most times include (in no particular order):

Lord of the Rings - Tolkein (over 10x)
Haroun and the Sea of Stories - Rushdie
Till We Have Faces - Lewis
Studies in Words - Lewis
The Chronicles of Narnia - Lewis (over 10x)
A Cry Like a Bell - L'Engle
Weather of the Heart - L'Engle
The Brothers Karamazov - Dostoyevsky
Zen and the Art of Motorcycle Maintenance - Pirsig (over 10x)
Father Arseny: Priest, Prisoner, Spiritual Father - Vera Bouteneff, tr.
Mossflower - Brian Jacques
Earthsea Trilogy - LeGuin

Alex
O..O
=o=