If you think that running anti-virus software is good for security, think again.
There have been multiple exploits lately of vulnerabilities in badly written, badly architected A/V software, such that an attacker can exploit the A/V bug to compromise your system.
Here’s the latest whopper: ZDnet.com.
I think a well patched OS may well be safer than one encumbered by these badly built “security” products. Wow.