Teachers get very little respect, or at least money as explained by (the) Dave Eggers, Ninive Calegari, and Daniel Moulthrop in today's New York Times.
Growing up I remember my mom constantly buying art supplies, collecting pine cones, egg cartons, and toilet paper rolls, and working on the weekend. My dad--who teaches high school--didn't have to purchase stuff for the classroom, but, man, did he work in the evenings and on the weekends. They were and are so good at what they do--it seems more of a calling than a profession. That doesn't mean they and their peers shouldn't get paid for their work, though.
Teachers are often liminal characters in kids lit. The good ones are the trusted adults who can still remember what it is like to be a child. While authority figures, they will sometimes let an intelligent child explore outside the rules. Think Dumbledore or Lupin from Harry Potter.
So, in honor of teachers I'm compiling a list of the best ones in children's books. I've asked over at Verla Kay's board for suggestions and so far the following books have been mentioned:
Middle-Grade Fiction
1. Sahara Special by Esmé Raji Codell.
2. Perfect Man by Troy Wilson.
3. There's a Boy in the Girl's Bathroom by Louis Sachar.
4. Frindle (and more) by Andrew Clements.
5. Chasing Vermeer by Blue Balliett.
Picture Books
1. Miss Nelson is Missing by Harry Allard (ill. James Marshall)
2. First Day Jitters by Julie Danneberg (ill. Judith Dufour Love)
From series, of course, there is always Ms. Frizzle of Magic School Bus fame and Miss Mackle of the Horrible Harry books by Suzy Kline.
I'll keep updating this list. I know there are many more great teachers out there.