As soon as I found out I was pregnant, I put Chicka Chicka Boom Boom by Bill Martin Jr., John Archambault, and illustrated by Lois Ehlert on my baby shower list.
I remember falling in love with this book when I was in elementary school. I loved the rhymes, the emotions, and the characterization of the letters.
As a child I especially loved "loose-tooth T" as my name starts with a "T." ;)
I love how both the hard cover and the board book include the upper and lower case of the alphabet. It's become a habit in my home that after we read the book, I point at the letters while singing the alphabet song.
If you want to make sure your book lasts as long as it can with your baby/toddler, I recommend getting the board book. We had a one-page casualty with the hardcover book that required a lot of tape.
While I highly recommend this book, I don't think this book is the best for teaching kids the sounds of the letters as this book relies on rhyming with the names of the letters.
Nevertheless, I love this book and I'm so glad my elementary school teachers read it to me so many years ago!
Board Book (Amazon)
Hard Cover Book (Amazon)