My favorite OVA? Well, I particularly liked Heya! The Return of Son Goku and Friends!, but I am a big DB fan to begin with. I guess I'd put FLCL, outside DB terms.
Movie, I'm going with Akira for a stand-alone, and for one based on a series, FMA: Conquerors of Shamballa. And, outside of shonen/action bits, I really loved Grave of the Fireflies, as depressing as it was.