In 2003 at the Laputa Animation Festival in Japan, 140 animation artists and film critics entered a list of 20 animations (films, TV series, shorts, etc.) they considered to be the best and most influential animations of all time. As a result, 150 films were compiled into one list by the festival board. The list I found was compiled by Cathy Munroe Hotes at the site I listed. As Hotes mentions, "This list fascinates me because it is...a snapshot of a moment in animation history." Fan art of Hedgehog in the Fog (the highest ranked animation) credit given to alexteri from the site Deviant Art.
There is an order of the list on the site with the films receiving the most votes at the top. I, however, have preferred to list films in chronological order as of late. There is a unique realization that reveals inspiration trickling throughout the course of film history by the likes of generations of talented and influential artists. Go see where each of the animations rank on the link provided.