Toy Story 3: This was the kind of sequel that needed to happen in order to provide more satisfaction to the overall story than trying to make a sequel to a movie that already had satisfying ends.
Toy Story 2: It's so great I can't even fit all of its greatness into this comment. The theme about everything coming to an end and whether we should accept.
Inside Out: Has such a good message about how we need all emotions not just joy and represents it extremely well.
Ratatouille: This is easily the most underrated pixar movie. It is funny, the animation of Paris is gorgeous, the characters are memorable, and it really sucks you into the environment.