yeah ive seen all of the movies available so far, and even a lot of the ones not available to the us.
id rank them like this.
first group: princess mononoke, spirited away,
second plave group: steamboy, nausicaa, porko rosso, howels moving castle. the cat returns, my neighbor totoro. my neighbors the yamadas
then the last group: pom poko, whisper of the heart, only yesterday, kikis delivery, castle in the sky. grave of the fireflies (could be in the second group cause its great work, but i wasnt as entertained)
they are all watchable though.