How does one do this? A separate HD?
I have nearly all my pics on web albums which is almost all I care about.
I suppose it depends how much data you are backing up. If it is only a few GB, then DVDs and/or online storage might be practical.
You could use USB flash stick drives but they can be a bit unreliable so never rely on just one. If you are going to use them, I'd suggest buying at least 2 and alternating them - use one on odd days of the month and one on even days. The chances of your HDD and
both your backups failing at the same time are pretty slim.
I use an external USB2 hard drive and some free backup software which I found on the internet. I've had to do one restore after my Windows registry got so screwed up that my computer wouldn't boot. I also had to restore my brother-in-law's system when his PC had problems. He used an external USB2 hard drive too, but he used Norton Ghost backup/restore software.
I suggest that you get the backup software to verify the backups after making them - there's not much point in trying to restore a corrupted backup!
Ideally, you wouldn't keep your backup(s) in the same building as the computer in case your house/office burned down or you got burgled and all the equipment was nicked.
Wikipedia article on backups said:
In 1996, during a fire at the headquarters of Crédit Lyonnais, a major bank in Paris, system administrators ran into the burning building to rescue backup tapes because they didn't have off-site copies. Crucial bank archives and computer data were lost.
!
If your data is sensitive and someone might be able to walk off with your backup, or it is online, make sure it is encrypted!