As well as archiving to CD , I have a copy on a USB enclosure type IDE hard drive , after all with the switch to SATA drives you must pay attention to which formats are going the way of the dinosaur , IDE is one of them but a USB enclosure should be safe for another 5 years or so. PCI slots are going away fast so don't count on being able to use a PCI interface card to read IDE directly in todays or the next generations of machines.
Ray