As much as I liked Incredibles and Ratatouille, my favorite so far is Monsters, Inc., which sadly didn't get the recognition it deserved after the first Shrek movie was a sleeper smash.
It takes a lot to get me to tear up at a movie. It's a Wonderful Life gets me every time, but I was not ready for the emotional punch at the end of Monsters, Inc. At the very end, when Boo said, "Kitty!" that did it. Thank goodness I was watching alone.