This will be tough for me, I don't read much fantasy...but I'll try it.
1. Favoritest and bestest of all is the Chronicles of Narnia by C.S. Lewis. Wonderful books that I have enjoyed for as long as I can possibly remember. I never complain when Pop offers to read them aloud, and I have more than once rented a book or two on tape from the library. (Of course, his Space Trilogy is exceptional, too, but Lal said only one series or book from each author.)
2. Running a very, very, very close second, if not tied, is The Lord of the Rings by Tolkien. Marvelous book...but I don't know if it'll ever be able to hold the same place as the Chronicles do.
3. The Lost Princess
or The Princess and Curdie by George MacDonald. Both very good books. The Lost Princess is another old favorite.
4. The Merry Adventures of Robin Hood by Howard Pyle. Is it fantasy? Well...mayhap not, but I highly doubt it's entirely historically correct.
And I don't know ifI have another favorite. As I said I haven't read much fantasy - the only other stuff I can think of is the trilogy His Dark Materials which I read the first of but so abhored that I did not continue, and Harry Potter, which I thought...I won't say...
and Mom banned it, so I can't very well read more than I have, which is only the first.
So in the fifth place, I will put a few other favorite books by the author's listed above: The Silmarillion (supurbly awesome), The Space Trilogy (by Lewis), and Phantastes (by MacDonald).