Nausicaä of the Valley of the Wind
Haven't seen a lot of Studio Ghibli movies, but always heard good things about this one, and my gf was in the mood for something anime related so we threw this on. Really enjoyed it!
A sci-fi/fantasy epic with beautiful art and animation, giant feeling action & world-building, and some strong environmental themes. Feels like Studio Ghibli's Dune
in a lot of ways, which I'd bet was a big influence.