I picked up a copy of The New York Times Essential Library of Children's Movies: A Critic's Guide to the Best Films Available on Video and DVD, written by Peter M. Nichols, a few weeks ago and have been meaning to post some comments about it.
The reviews of the films are great, but it's not a terrific resource for, um, building an library of kid's movies--primarily for two reasons.
First, it considers "children's movies" anything up to age 18 apparently. This isn't terribly useful as I regard older teens as being able to watch almost anything (depending on the child, of course)--at least in terms of subject matter.
Secondly, some of the age ratings it gives are ludicrous. I wonder if Mr. Nichols has children!
For example, Chicken Run, one of my 4-year-old's favorites is listed as only appropriate for kids six and up. Monster's Inc. is described (in part) as being "too intense for three to five-year-olds"? Shrek is listed "without reservation...this is fine entertainment for children of all ages"!?! You get the idea...
E.T. is listed as the "greatest children's movie ever made"? I also found the inclusion of The Little Mermaid wrong-headed. I have only scorn for that film, perhaps the greatest example of What's Wrong With Disney.
There are some great recommendations, such as Abbot and Costello Meet Frankenstein, The Bear, and many others. While I do recommend this book as a guide overall, be sure to take the author's age suggestions with a grain of salt.