I have few favorite books because there are so many of them that I love, but Lily's Purple Plastic Purse by Kevin Henkes is one of my favorites. In the last few years, the language used in children's books has changed from formal and boring, to modern and conversational. These books are not always great for grammar examples, but they are so much fun to read.
Lily is a sassy, school-aged mouse who loves her teacher, but one day she comes to school so excited about some goodies she received from her grandma, including a purple, plastic, purse (who wouldn't love that?). These things distract Lily and the teacher finally confiscates the items until the end of the day. Lily is livid and her favorite teacher quickly becomes her least favorite teacher. The story continues as Lily learns her lesson, and all is right in Lily's world again. Cute, cute, cute!