Lupus Inu said:
Grave of the Fireflies - Good.
Nausicaä of the Valley of the Wind - Great.
Castle in the Sky - Good.
Whisper of the Heart - Avoid. Depends if you like warm fuzzy slow stuff, if you do, give it a try.
Kiki's Delivery Service - Good.
Princess Mononoke - Great.
Metropolis - Great.
My Neighbors the Yamadas - Not seen.
The Cat Returns - Ok.
Whisper of the Heart is excellent! Don't listen to the madmad!
My Neighbours the Yamadas is quite a departure from the usual Ghibli style. Erm, imagine an anime where every scene had to be sketched by the animators in five minutes - that's kind of what it's like, except, really good.
Almost all of the Ghibli films you've listed follow the same kind of slow, fuzzy and nice story pattern. I quite happily can curl up in bed and just watch Ghibli for hours, but really, if you want action or anything even remotely mind-taxing, you may want to look for something else. Of course there are exceptions; Grave of the Fireflies is essentially a war drama, following the lives of a brother and his young sister. It's extremely moving, and generally very well accepted, but you'll need pleanty of tissues when watching it. I own it, and have only ever watched it once, because although it's excellent, it's very heart-wrenching.
Nausicaä, Castle in the Sky and Princess Mononoke are the three other exceptions, as they're fairly high-paced action adventures when compared to the others (but still very Ghibli). Castle in the Sky and Nausicaä both have sci-fi undercurrents, whereas Mononoke is more centered around the magic of nature and such.
All of them are worth a watch.
