Yeah, A Bug’s Life hasn’t stood up so well. It’s the most cliche IMO. The story is weak and the characters are cardboard cut-outs.
Pixar’s best I think is Ratatouille (though WALL•E is equally as good). Ratatouille impressed me because the story and characters largely escaped the weighty commercial remit that tars a film with a pre-disposed requirement to fit a cliche, sell a lot of merchandise (e.g. Cars). Ratatouille is not a film your average film-exec would ever let see the light of day. It lacks explosions :P