A neat little feature of School Library Journal's online edition is the book pick of the week. For March 27th, the choice is a picture book, The Boy Who Loved Words, written by Roni Schotter and illustrated by Giselle Potter. Trot over to SLJ, and read the review.
Another good picture book with big words—well, one big word, at least—is Veronica, by Roger Duvoisin. The story of a hippopotamus who wants to be "conspicuous" was recently re-issued by Knopf, and Duvoisin's illustrations of a big-bottomed hippo in the city are hilarious and endearing. If you love picture books, you'll want this classic for the home library. Don't forget Duvoisin's Petunia, too.