Passporter was a perfect choice! I think it has the clearest, most easy-to-find-and-decipher information for a first-timer.
I know that Unofficial Guide is sooooo intimidating - that's why it's perfect for those of us who are so obsessed, we can't get enough!
The Birnbaum's for kids will help the little one get excited. My parents bought one for my sister on our first trip and I ended up stealing it from her cuz I liked it so much.....and I was 15!
I never recommend the full/regular Birnbaum's to anyone. I just think it provides this glossed-over, promotional dip into Disney and doesn't give you any of the IMPORTANT information! I can't imagine going to Disney for the first time after having only read Birnbaum's. It would be a huge (unpleasant) shock.