Yes, poetry. While we usually stick with prose when reading to our children, every now and then I like to read poetry to them. I find that they enjoy the rhythm, even if the storyline isn't readily apparent to them. When Kieran was quite small, I read various Shakespeare and Coleridge to him, in fact.
More recently, I decided to read Poe's "The Raven" to Charlotte. She loved it and even asked me to read "the chamber door" to her for a few days after I initially read it. Far from being inaccessible, poetry can be quite a hit with children, with the alliteration and rhythm and imagery. If you've not read any poems to your child, why not start?