I do and I bought it for my kids hoping it'd be their first book too. It wasn't... the first book that Elliott read was Go Dog Go and I'm ashamed to admit that I have no idea what the first book was for the other two. What a mother, eh?
Anyway, my first book was Hop On Pop. There are so many images from that book that are stuck in my head like all the kids sleeping (except for one) in the same big bed or Pat about to sit on the cat ("No, Pat, no, don't sit on that!"). And I can never hear about someone with the last name Brown without thinking (usually internally)"Mr. Brown is upside down".
That book was the foundation for reading all the books I've since read. So because of Hop On Pop I can read all the chick lit I want. Thanks Dr. Seuss!