One concern of mine is the responses seem to summarize:
A. You have a TDR and no worries
B. You don't have one, don't think you'll get the funding (ever) so just go with the cheapest route
I've taken these generalizations to the extreme, but to omit any discussion of how digital preservation files might be saved (other than CD-R and HDD), in my opinion, is the intellectual equivalent of sticking your head in the sand.