Great reviews here. One item that I haven't seen mentioned...is SO obvious:
Star Trek II is a very soft, space-based version of Moby Dick. Indeed, Khan has Moby Dick on his shelf of books. In this case, Khan is Ahab and Kirk is the whale. Multiple times during the film, at very classic moments, Khan's dialogue is straight (word for word) out of Moby Dick, or changed just to fit into the context of space.
For example:
Ahab: "I'll chase him round Good Hope, and round the Horn, and round the Norway Maelstrom, and round perdition's flames before I give him up!"
Khan: "I'll chase him round the moons of Nibia and round the Antares maelstrom and round perdition's flames before I give him up!"