I managed to catch Spirited Away on TV back in around January 2010 whilst flicking through channels, and I was absolutely blown away by it. I've not seen it again since, and I don't think I ever will simply because of the fear that it won't make me feel how it did when I first watched it. It's truly brilliant, probably one of the best films I've ever seen. I really do need to watch some of these others to see how they compare.
I also ended up watching Tales From Earthsea via channel flicking and whilst I certainly did enjoy it I was surprised to hear that it was made by Studio Ghibli. I did some research on it afterwards and apparently the author of the book that it's based on wasn't too happy with it