That's not cool, that's treating the symptoms instead of the cause. True security would prevent viruses and malware from infecting the system in the first place.
I run Firefox 3.6. I've been using Firefox ever since 1.0, after a user posted about it on a forum I used to visit, which started a debate over how insecure IE6 was. Since then, I've never looked back.
Firefox has some really nice extensions for security, such as AdBlock Plus (yes, I consider blocking ads to be part of security) and NoScript, the latter which pretty much serves as my anti-virus because it only enables scripts to run from my whitelisted domains. To date I've probably blocked at least five or six browser exploit attempts. While many users ran around as though the sky was falling after catching Trojans from poisoned websites, NoScript protected me by making sure that the Trojans couldn't even touch my system due to the off-site scripts not even being allowed to run.
To users of IE6: Welcome to the new web, where tabbed browsing is a minimum requirement feature and alpha-channel PNGs are seeing common usage. Please, just get a better browser.