My workflow involves creating a master of projects by saving that in the DNxHD (for PCs) or Prores (for Macs) format. I then archive this on a data dvd . I use this master to make whatever kind of copies I might need in the future, like h.264 for distribution or whatever.
This might not apply to your particular needs but is generally regarded in the industry as a good way to do things.
Tom Daigon
PrP / After Effects Editor
HP Z820 Dual 2687
64GB ram
Dulce DQg2 16TB raid
http://www.hdshotsandcuts.com