This post from C-Monster explains why if we as artists want our work to outlast our own mortality, we should pay as much attention to the archival qualities of our materials. Why one should not make artwork out of pop tarts or animal carcasses encased in formaldehyde.
Having said that, it is still my contention that the art-form that lives the longest is totally not tangible, poetry and stories. We are still reciting Homer, we are still telling the oldest tales, even when they are in comic books, video games and Battlestar Galactica. The actual totally archival medium is the human memory, the human need to tell stories to each other and to our children.