Excellent discussion !

A physicist Feynman once asked his class, "If all but one of all human learnings would stop and we must enter a long, dark period, what should be left for posterity ?"
He suggested arithmetic, the decimal numbers, to count, to add, to do the four arithmetic operations of addition, subtraction, multiplication, and division. From that alone, and some stuggling, all of science can be recovered from scratch. Of course, the recovery would be closer to rediscovery rather than reconstruction.
Playing on a similar note, if I could choose two, I'd leave literacy; one good alphabet (IPA ?), and some songs to go with it. From that all liberal arts can be recovered with some effort not taking more than 5,000 years.
If I could choose three, I'd definitely choose historical doc's on a DVD. (Is that big enough to store all the world's historical texts ?) To me history is what make the particulars, gives the local, ethnic, traditional flavors to each group of people. Geography and language should be a part of the historical info.
As for WWII, so much has happened since the late 1800's that shaped my country to be what it is now, and is setting the limits and possibilities for the future. So I think recent history of say 150 years is very much alive. History can be so illuminating that the difference between knowing and not knowing would make a qualitative difference for me. Moving from ignorance to enlightenment involves reading and thinking in historical terms, and should keep me busy and happy for a long while.