I grew up practically worshiping Calvin and Hobbs. The Farside was also a favorite. Now a days I dont really have a favorite, I just kinda browsa through. I guess the spirit of love for comics endes when Bill Waterson retired.
FBOFW is my all time favorite comic. I also enjoy Doonesbury, Dilbert (a surprising amount of what they cover applies to the education field,) and Garfield. Sometimes "Get Fuzzy" is extrememly funny, but it runs hot and cold. There are others that I read regularly as well.
I miss Calvin and Hobbes and The Far Side.
I always recommend comics (either from the paper or the web, or bound in books) to mothers of kids, usually boys, who are reluctant readers. It's a wonderful way to get kids reading. Nowadays you have graphic novels as well.