I personally stopped running any virus checking software a while ago. It’s my opinion that these signature-checking anti-virus programs were useful back in the days when installing software meant carrying a floppy disk from one machine to another, but since viruses today get spread at the speed of the Internet (or, more accurately, the speed of Microsoft Outlook), it’s impossible to keep anti-virus software up to date with the latest stuff. Rather, it’s much wiser to avoid doing risky things (like downloading cracked warez from newsgroups, or opening any suspicious email attachments). Combine that with personal firewall software that detects suspicious activity rather than specific virus signatures and that’s all the protection you’ll ever need.

However, I hesitate to tell the general public to drop their virus checking software. Here the analogy to biological viruses is appropriate — as long as most people keep running their outdated virus scanners, they’ll keep any ancient viruses from spreading again. If everyone were to stop, some of those nasty old buggers would come back to haunt us.