Originally Posted By: Dignan
Don't buy anything, just install Microsoft Security Essentials. It's the most lightweight program I've found for this sort of thing, and it gets high marks from every report I've seen on the subject.

This is all I do if I'm forced to install something when in Windows land. Paying for security software always felt like paying mob protection money.

Originally Posted By: Dignan
Now, queue the many people on this board who don't think you need antivirus.

If I was a day to day Windows user today, I would have something installed. Over a decade ago, yeah, I didn't feel the need for virus protection. Most back then either exploited Windows machines directly connected to the internet (not behind a router/NAT/firewall setup), or were the trojans from the bad parts of the internet. These days, the malware/viruses come from plenty of legitimate sources, either via an ad banner, or a site being hacked to inject the malware.

Thankfully on OS X, Apple is staying on top of the issue for the most part. They were a bit slow to address the vulnerability in Java, but have now responded with not only a patch, but also a cleaner for anyone infected. Turns out, none of my systems were vulnerable anyway, but good to see the response. Same thing happened with the last trojan spread malware, Apple just built the cleaning/detection into the OS behind the scenes. So far nothing targeting the Mac has hit rootkit like levels. If it does, then maybe I'll consider realtime security software.

The modern Linux threat seems to be from having a repository compromised. It's happened a few times, but the damage seems to be pretty minimal before someone notices. Or just installing a completely untrusted distribution, such as the recent "Anonymous Linux".