My favorite books I read when I was a kid were The Dark is Rising series, by Susan Cooper. If I had to pick a single favorite out of the series it would be The Grey King, but really the whole series is great. I still read it now and again.
Another good one, not very well-known, was The Pushcart War by Jean Merrill… a funny but barbed little story.
That’s an Eric Carle book… my girls loved that one too. 
I’ve said it before and I’ll say it again:
The Wedding Procession of the Rag Doll and the Broom Handle, and Who Was In It
One book that just about every kid loves is called something along the lines of “The Stinky Cheese man and other fairy tales”
I found it hilarious for a kids book
Winnie The Pooh (not the Disney version)
A Pocket for Corduroy by Don Freeman
The Reluctant Dragon
From the Mixed-Up Files of Mrs. Basil E. Frankweiler by E.L. Konigsburg
The Chronicles of Narnia by C.S.Lewis
The Cricket in Times Square by George Selden
The Light Princess (and other books, too, by George McDonald – the edition of this one that I had was illustrated by Sendak )
I still love The Westing Game by Ellen Raskin.
Anything by John Bellairs, particularly The House With a Clock in It’s Walls .
And another vote for anything by Roald Dahl.
The westing game! I tottally forgot about that. I still love that one too. the other books by Ellen Raskin are just as good . Geez , it seems like doper minds think alike.
It’s The Stinky Cheese Man and other Fairly Stupid Tales. Don’t remember the author, though.
My favorites would have to be A Wrinkle in Time, by Madeline L’Engle, The Lion, the Witch, and the Wardrobe, by C. S. Lewis, and The Hobbit, by J. R. R. Tolkien. And their respective sequals.
I’ll have to second (or third) the nominations of The Chronicles of Narna by C.S. Lewis and the A Wrinkle in Time series by L’Engle.
Me too on the C.S. Lewis and Madeline L’Engle. They played heavily in my childhood and I still go back and read them occasionally. My favorite picture book as a kid was Miss Susy by Miriam Young, illistrated by Arnold Lobel. It’s turned out to be my 2 yo son’s favorite too.
Where the Red Fern Grows, followed by My Side of the Mountain and Bridge to Terabithia.
oooh, I see some of my favorites already listed… I can’t pick just one, though.
The Hobbit (and Lord of the Rings trilogy)
The Little Princess & The Secret Garden - by FH Burnett
National Velvet
Lochinvar Luck & Lad: A Dog - by AP Terhune
almost ** any ** Nancy Drew, but fav is The Hidden Staircase
And thanks to Romola for Where the Red Fern Grows, I’d forgotten about that wonderful story!
My favorite children’s book is The Diamond in the Window by Jane Langton. An amazing book, well worth reading and re-reading.
I’m surprised that no one has mentioned E.B. White yet. You can’t go wrong with Charlotte’s Web or Stuart Little.
The all time best has to be “Everyone Poops.” Kids love it.
I also vote for The Stinky Cheese Man and of course anything by Dr. Suess.
I hate the real cutesy ones like Barbie books (uuugh), but when my kids got them as gifts, I would read them and make Barbie sound like a grizzled old barfly, and Skipper like a kid from Village of the Damned.
SpoilerVirgin
I remember checking The Diamond in the Window out from the library over and over again… is this book still in print? What an excellent story it was. In some ways it reminded me of all of the E.Nesbit stories, but it was a bit more sophisticated.
I am sure that E.B.White was mentioned in the former kids’ books thread.
Another favorite of mine was The Jungle Book by Rudyard Kipling.
I can’t remember the author, but I loved “A Cricket in Times Square” as a kid.
Also, you can never go wrong with Dr. Suess. My personal favorites are “The Lorax” and “The Sneetches.”
Shadow Castle, The Wizard of Oz books and anything by Enid Blyton.
I also read Gone With the Wind when I was 12…I think that was somewhat ambitious, but I wouldn’t count it as a kid’s book.
The Very Quiet Cricket is a good one too.
I just remembered how much I liked " Little Women" when I was a kid. Also, any of the “Anne of Green Gables” books I think there were like 7 of them
Hmm…I think I still have a few copies of my Tom Corbett, Space Cadet series around here somewhere (Along with my Tom Swift and His Repellatron Skyway…)
I forgot about Where the Red Fern Grows. A teacher read that to us in class! I still have copies of The Cat Ate My Gymsuit and The Witch of Blackbird Pond and It’s Like This, Cat.