So my top five had to grow this week so that we could fit all six books in. This is courtesy of mugglenet.com. They have lists of funny and fun quotes from the books. I couldn't find my favorite though. When Dumbledore says he has a few words for the beginning of term and they include "nitwit" and other great nonsensical words!
Book 1-"Sir — Professor Dumbledore? Can I ask you something?"
"Obviously, you’ve just done so," Dumbledore smiled. “You may ask me one more thing, however."
"What do you see when you look in the mirror?"
"I? I see myself holding a pair of thick, woolen socks."
"One can never have enough socks. Another Christmas has come and gone and I didn’t get a single pair. People will insist on giving me books."
Book 2-Warlock D. J. Prod of Didsbury says: "My wife used to sneer at my feeble charms, but one month into your fabulous Kwikspell course and I succeeded in turning her into a yak! Thank you, Kwikspell!"
Book 3-As though an invisible hand were writing upon it, words appeared on the smooth surface of the map. "Mr. Moony presents his compliments to Professor Snape, and begs him to keep his abnormally large nose out of other people's business."
Snape froze. Harry stared, dumbstruck, at the message. But the map didn't stop there. More writing was appearing beneath the first.
"Mr. Prongs agrees with Mr. Moony, and would like to add that Professor Snape is an ugly git."
It would have been funny if the situation hadn't been so serious. And there was more...
"Mr. Padfoot would like to register his astonishment that an idiot like that ever became a professor."
Harry closed his eyes in horror. When he'd opened them, the map had had its last word.
"Mr. Wormtail bids Professor Snape good day, and advises him to wash his hair, the slimeball."
Book 4-Dudley had done the thing he was threatening to do since age three: He had become wider than he was tall.
Book 5-"Don't put your wand there, boy!" roared Moody. "What if it ignited? Better wizards than you have lost buttocks, you know!"
Book 6-"Oh, there you are, Albus," he [Slughorn] said. "You've been a very long time. Upset stomach?"
"No, I was merely reading the Muggle magazines," said Dumbledore. "I do love knitting patterns."