I think magnetic tape is better to store data for 100 years...
Recent tests say that cdrs are not very reliable, not even the more expensive brands... the data will just end up getting corrupted in 20 years or so...
Might be true. I think some of it can be attributed to how the media is stored, while quality of the media is important too.
(Personally, I've had CD-Rs corrupt in less than a years time.. Granted, they were the cheapest I could find, but they should last a LOT longer than that.)