I have always loved "Where the Wild Things Are" by Maurice Sednak.
"The Polar Express" by Chris van Allsberg is a little long, but it's a great story and the illustrations are beautiful.
I get a big kick out of Sandra Boyton's books, they're short and sweet and the pictures are funny my favorite is "But not the Hippopotamus".
Ian Falconer's books about Olivia get my girls (4 and 2)giggling like crazy (it's a little girl pig, the books aren't too girly though, she has a little brother).
Peter Spier has some books without words, I have "Rain" it's about a brother and sister and what they do on a rainy day. He has one about Noah's Ark and possibly others. I like them because you can just talk about the pictures with the kids, it helps my eldest daughter not to be too frustrated about not being able to read too well yet. They're also good because you can drag them out and make them take a long time or whip through them quickly, if you don't have much time.