Lupin III: The Castle of Cagliostro (1979)

Lupin at his “gentleman thief” best. Watching Part I made me appreciate this much more—Miyazaki and Takahata directed the second half or so and you can see Cagliostro coming together there. Their parts of the TV show are often hamstrung by ill-fitting child-friendliness, episodic status quo, and an unnecessarily narrow setting (central Tokyo), but here they make something beautiful that's more true to the idea of Lupin.