Emma Dilemma is a wonderful book of "big sister poems" written by Kristine O'Connell George. Any child who is a big brother or a big sister can relate to this book. The narrative poems read like a story and have a very touching ending and thought-provoking ending. You can find this book and other poetry book recommendations on Laura Candler's poetry resources page.
Seven Blind Mice by Ed Young- A book for any age, which not only introduces color, but also explores philosophical questions concerning perception and reality. (Nonni McHale is sure to love the "surprise" at the end.)