Best Pixar Film

Hello All,
I have to write a persuasive speech for my class this weekend, and was going to be debating which Pixar film is the best. I know its all about opinion, but that's what a persuasive speech is. I'm focusing on elements of storytelling, animation or developments in effects. So, please, if you comment, give solid reasoning as to why you feel the way you do. I need qotes and ideas from all sides from good animators, and thought this would be the place to turn. And please don't comment on other peoples remarks, I want this to stay light and fun. No bashing! Let me know what you think. Thanks for your help!

-mole