My current favorite book for precocious little girls is Fanny by Holly Hobbie. It deals wonderfully with many issues little kids face, such as being different, being left out, and not getting what you want from your parents. Fanny takes thing into her own hands, solving her own problems. But the best part, is I used this book to introduce my DD to the concept of recursion.

Of course, my all time favorite book to read is Wet Dog by Elise Broach. It's really a fun to read poem combined with amazing illustrations by David Catrow (who I think has become by wife's favorite illustrator... which is really saying something if you knew my wife and her artistic capabilities).