i've got loads of old cables. Well, about 4 boxes full of em. Just store them somewhere.
The other month I threw out some old cables (paralell cables) that I'd had for about 15 years and then about a week later realised I could have done with them actually, as i bought a couple of LCD units of ebay that required connecting to the paralell port. So dont throw them out.
Also, Old IDE cables make excellent wires for soldering chip pins and things like that. (if you need to do multiple pins, just leave the cable joined for a neat finish)
But, IEC style power cables what to do with them? I must have about 30 of the things in a bag.