3. Mike Wazowski - Monsters Inc
He might have the world's most annoying voice (sorry Billy) and look like a bogey on legs but Mike Wazowski is the heart and soul of Monsters Inc. Sure, Sully is big and fluffy but it's Mike that makes the movie what it is and gives it it's real heart, providing all the laughs, usually at the expense of Sully's straight man. What sets Mike apart from other sidekick's such as Dory or Mater is that Mike genuinely loves his best buddy and cannot imagine a life without him. They have been friends for what seems like forever (an idea explored in the upcoming sequel) and are nothing without each other. Such a bond almost makes these two contenders for the ultimate Pixar friendship but that honour is saved for another pair.