Though I enjoyed A Bug's Life enough, it seemed like Pixar got too cocky with that one. Toy Story was a hit so they thought they could do no wrong.
And I was pleasantly surprised with Cars. I had no hopes for that one, like Pixar ran out of ideas and Disney was looking for a way to associate their Autopia with a movie. But it was actually pretty good.
I still haven't seen Monsters Inc., which I've been meaning to.
Monsters Inc is my favorite, it's just so sweet and heartfelt, so immensely touching. Just a wonderful movie.
I also loved Incredibles and Finding Nemo. Cars was a pleasant surprise, seeing as I thought it would be their first real "miss".
Of course, Toy Story is a classic, a very important film that paved the way for so many others.