I'm looking for suggestions too, thanks for posting.
I've read, with my 4.5 year old boys:
Stuart Little
A Mouse Called Wolf
The Wonderful Trip to the Mushroom Planet (1950s scifi, recommended by the librarian - they loved it, and I loved the short chapters!)
Charlotte's Web
The Day the Fish Went Wild
We tried to read The Wind in the Willows, but it didn't hold their interest - I think the language was a little too advanced.