The Fisher King just destroyed me when I saw it in the theater. Brilliant work. (And, in my opinion, Gilliam's best work as director, too.)
One Hour Photo ... haunting performance. Just haunting.
Dead Poets Society ... there's a reason that monologue is being used in commercials today 25 years later.
In movies I liked him best when he wasn't doing the crazy, frenetic thing, but when he unleashed it in his stand-up, he was magic. 16-year-old me could recite the entirety of "Live at the Met" (including voices). Even the stuff I didn't understand.
He was a giant and he will be missed.