There is only one children's book that makes me cry. It's Someday by Alison McGhee.
Some say it's not a book for kids, but for mothers. Still, my daughter loves it ... so much, she has it memorized. The author, Alison McGhee, calls it a journey through motherhood. It's not only a great book, but I love the illustrations by Peter H. Reynolds too.
If you haven't read it, it's similar to the very popular Love You Forever, but in my opinion, is better. (If you're a fan of Love You Forever, click here to read the true meaning of the book. It's not what you think.)
If you know someone who is having a baby, I suggest this book as a gift. It's the best.