I have seen various Ghibli movie's over the course of my life and Princess Mononoke is the undisputed champion imo. I loved the scenes between Okkoto-nushi and Moro as well as the spirit god scenes. From animation to music, studio ghibli was a legend back in the days and their films still hold up well.
In my eyes, the films that Studio Ghibli created, had an impact that put them on the level of The Godfather trilogy.