On a "desert" island, I'd bring a canopy and water.... :rofl:
Sorry, just had to in light of the recent controversy... On a deserted island, now....
Music: the Backakademie edition of the collected works of Bach. If that counts, since it's 172 CD's. If not, something by Floyd.
Movie: I'd have to second the Lord of the Rings trilogy or the Pirates of the Caribbean series.