I read that adblock helps a lot too
the addon for chrome firefox, and most all browsers. I'm not sure why? I'm thinking when someone visits a site that has ad's all over it, some of those ad's are flash based, and could contain the virus, and even though you may have flash installed, when adblock blocks the ad, it can't infect you? How true this is, I don't know. But I can say that adblock blocks everything, even youtube ad's...
When I got my new laptop a few weeks ago, I had forgotten to add adblock, and I went to youtube, and I was shocked at all of the ads that I'm not used to.