Great tier Ghibli:
1. The Wind Rises (風立ちぬ)
2. Castle in the Sky (天空の城ラピュタ)
3. Spirited Away (千と千尋の神隠し)
4. Nausicaä (風の谷のナウシカ)
5. Princess Mononoke (もののけ姫)
6. My Neighbor Totoro (となりのトトロ)
7. Howl's Moving Castle (ハウルの動く城)
8. Kiki's Delivery Service (魔女の宅急便)
9. Whisper of the Heart (耳をすませば)
10. From Up on Poppy Hill (コクリコ坂から)
11. Porco Rosso (紅の豚)
12. Arrietty (借りぐらしのアリエッティ)
13. When Marnie Was There (思い出のマーニー)
14. Ponyo (崖の上のポニョ)
15. Pom Poko (平成狸合戦ぽんぽこ)
16. Tales from Earthsea (ゲド戦記)
17. My Neighbors the Yamadas (ホーホケキョとなりの山田くん)
18. The Cat Returns (猫の恩返し)
Now, a couple meta observations:
Movies are like dishes: when they're bad, usually it's because of a bad cook or bad ingredients. Yet, Ponyo is prepared by a genius cook using pretty good ingredients. What happened?
1. The story should stand on its own two feet even for those who understand none of the hidden meaning
2. All symbols should add a layer of meaning that reinforces the initial story and its message, not detract from it
Not bad because out mediocrity, but bad out of genius -- even a genius doesn't hit the target 100% of the time.