The complete works of -
The entire Beastie Boys, Beatles, Led Zeppelin, Rage Against the Machine collections (at least) anything with Jack White ... MIA, Santogold and Missy Elliot for sure... oi this is hard! I have a lot of "mixed tapes" that I would include for sure to keep things interesting. Good question!
I think mine would contain a lot of classical / new age type of tunes. Maybe some works of Palestrina too. And "Cosmos" on books on tape. Having Carl Sagan's voice and the music of the show describing the reasons for exploring space while staring into the vastness of space and an ever shrinking Earth would be quite something..