H.B.
My husband and I (we take turns on a book by book basis) just started reading chapter books one chapter a night to my 4 year old at bedtime and we're all loving it. I've always been a voracious reader and am enjoying rediscovering the books I read in early grade school, and experiencing them as again as he hears them for the first time. We're enjoying:
Wizard of Oz books - Frank L Baum
Charlotte's Web - EB White
JRR Tolkien (one written for younger kids called Roverandom)
And looking forward to getting into Beverly Cleary (Mouse and the Motorcycle, Henry Higgins, etc)
After that... we'll see, maybe Chronicles of Narnia, or I'd also like to find some good historical fiction so we're not just pumping his head full of fantasy, fun as it is. :-) That said, it's been wonderful watching his imagination take flight as all the new ideas, more advanced vocabulary (especially in the area of adjectives!) and the idea of "smart" made-up words enters his mind.
I also love the Shel Silverstein books of poems
Perhaps Roald Dahl (The Twits, Matilda, Witches, Charlie and the Chocolate Factory) - I enjoyed them as a child but they're kinda scary when I look at them again through adult eyes!
We found Rudyard Kipling to be a bit, well, shall I say, innapropriate for this day and age (lots of n-words and racial slurs and such - simply written in a different time for a different audience, and probably not transferable to today)
I'd also love to get ideas from other people!