I just read The Milkman, by Carol Foskett Cordsen and illustrated by Douglas B.Jones, seven times in a row to Gregory.  I think he likes it.  And better yet, I like it too.  It has a nice rhythm to the rhyme, the illustrations are fun (a sort of 50-ish advertising style) and the story is peaceful but interesting.  If you have a little one about, see if your library has it and take a look.