A hard-drive crash from an infection or mechanical failure is an unlikely event, but it's a catastrophic one. Sure, backups can be time-consuming, but weigh the few minutes you might spend securing your data against the painstaking task of reconstructing it, or worse, losing it forever, and there's no question which is the preferred alternative.

CDs and DVDs aren't the only way to back up your data, nor are they the most convenient. The best method is the one that's easy enough that you'll actually do it, so keep that in mind as you decide which way to go. You'll also need a backup for your backup--one copy at your physical location and another offsite, in case of fire, flood, theft, or other disaster. Ideally, both should be continual and automatic. Here's a guide to the most popular methods: