Storage medium for longevity of data?

This topic came up on slashdot a week or two back, and I have been thinking about it ever since. And it's even on-topic, when asked a certain way. How resilient are today's storage media? In particular, is our classic computing data (tape/disk images, scanned documents, etc.) archived adequately enough that it's going to survive the next few centuries? One slashdot poster postulated that some EMR event (possibly the next magnetic pole reversal, or some sort of solar phenomenon) could wipe out nearly all of our magnetically stored data. Another user pointed out that even CD-ROMs expire eventually. One thing that came to my mind was our venerable friend the paper tape (an example of why it pays to remember the history of computing). I think it makes a darn good solution for archiving data and locking it away in a vault for a few millenia, provided some research was put into developing a tape paper (or other material) that would last longer and store data more densely than our traditional paper tape mechanisms. Any thoughts? -- Jeffrey S. Sharp jss(a)ou.edu