I tend to agree with the Epicurean from Seamus Heaney's country . . . there are only a few true classics.
To me, the classics to which all D&D players need to be introduced are, in historical order:
- The Odyssey. (In a pinch, hope they've at least seen "Troy", "Jason and the Argonauts", "Empire", or any other sandals and togas type movie.)
- Beowulf, preferably the Seamus Heaney version
- Robin Hood, preferably the 1930s Errol Flynn movie version
- The Knights of the Round-Table, preferably Monty Python's version
- The Hobbit and the Lord of the Rings
- Star Wars
- Conan the Barbarian (198x movie)
- The 13th Warrior (Beowulf reinterpreted)
- LOTR movies
That's a complete education, IMHO.
Lots of things are good for extra credit, like H.P. Lovecraft, "Willow", "Braveheart", those little Osprey books, or watching "Battlefield Britain" . . .