This is sort of my order of preference, omitting those I haven't seen or wouldn't watch again:
Kiki's Delivery Service
Whisper of the Heart
Nausicaa of the valley of the wind
The Disappearance of Suzumiya Haruhi (must see the series first)
Howls Moving Castle
Summer Wars
Princess Mononoke
Spirited Away
Ponyo
My Neighbor Totoro
My Neighbors the Yamadas
Just paste them in the search bar
here for synopsis and reviews and such.
His and her circumstances is a series, not a movie