Peeves and McGonagall (Deathly Hallows Spoilers)

Even though McGonagall is a very strict teacher, she definitely has a sense of humor, and unlike Filch, she's not adverse to a little chaos for the right reasons. I love her helpful little aside to Peeves in Order of the Phoenix, and in Deathly Hallows, she and Peeves seem to be on the same team again when she orders Filch to find him, and later we see him dropping Snargaluff pods on the attackers.

I took a peek at McGonagall's Wikipedia page and was interested to learn that her surname comes from a 19th century Scottish poet by the name William Topaz McGonagall, hailed as one of the worst poets ever to grace the English language, which gives her another connection to Peeves! Though I must say, his victory chant - "We did it, we bashed them, wee Potter's the one, / And Voldy's gone moldy, so now let's have fun!" - is pretty catchy...