I've had to fix other people's computers because of viruses, but never my own. I install a good anti-virus program and forget about it (AVG, Avast or Microsoft Security Essentials). But I also don't visit sketchy sites or open email attachments from people I don't know. I also don't use internet explorer except at work where I have to for development and testing. The people whose computers I've had to fix aren't that savvy and probably should be on Macs just for the virus "protection."
