My 18-month old has only recently become interested in books. He especially loves anything that has a rhythm when you read it.

His current faves (all have a great rhythm and all have excellent, though widely differing, illustration):
Hand, Hand, Fingers, Thumb
Barnyard Dance
The Remarkable Farkle McBride
Chicka, Chicka, Boom, Boom
Bam, Bam, Bam

Although I bought it for me and not my kids, (I was taking an illustration class in college — pre-motherhood — and picked it up to study the illustrations), Bam, Bam, Bam has become a family favorite. It’s a book featuring demolition and construction and I would recommend it as a first read-aloud for any child that likes a good loud noise. The illustrations are big, bright and simple with great colors. And if you shout out the Bam, Bam, Bams and Slam, Slam, Slams, the kids are hooked.

P.S. — 11 of the best designed board books.