This is one of the reasons I don't have a back-up solution.
I do make some backups, anything I can't afford to lose, gets put on a DVD, a USB stick / external USB HD and on my webhost (off-site).
Mind you, I've learned to keep the amount of stuff I need to keep around to a minimum, murphy's law applies always...
When you can't afford for something to go wrong, it will go wrong.
If it can be even worse to go wrong at a later time, it will go wrong at that later time.
The frustration with failing backup systems and such is something I'm avoiding =P (I'm of the type that realises the backup system becomes more important than the workstation, except you have a centralised point that can fail instead of one of the X workstations)
Keeping it as simple as possible reduces the amount of things that can go wrong!