Spirited away has a shiny fairground visuals but really dark undercurrents. Not my favorite even if technically is great. Mononoke is deliberately gross and confusing in some moments. Not for small children.

Ponyo or Totoro would rank much higher for me. Ponyo is really smart in many aspects. The Tomb of fireflies is a terrible and depressing black hole, but maybe a necessary experience. Porco rosso is the opposite, light and very enjoyable.

In any case this article is related clearly with the fact that Mononoke is again broadcasted in the movie theaters just this week.