Personally I think that great quotes are the ones that make you laugh.
After being cast as Harry Potter: "I think I'm a tiny bit like Harry 'cos I'd like to have an owl. Yeah, that's the tiny bit, actually." --Daniel Radcliffe
This guy goes into his bank to close out his morgage. The teller hides under the desk and calls out, in a spooky voice, "theres no one here."
"Yes, there is, I saw you."
"No, there's not."
"What's that voice then?" asks the guy.
"It's a person."
"No it isn't."
"Come on man, you can't stay under there all day."
"Yes I can. I've got sandwhiches."
--comercial from virgin radio