Really this would whole heartily depend on your definition of a virus. To acquire a "virus" (a local trojan horse, or key log) you must go find said virus and download it, not an easy feat by any means. You must seek out this program, which will not be easy to find as Apple invests billions in litigation, and securities, so you gotta go find it. Then you gotta install it. It doesn't sneak in with some app, or some email, you must find and install it. You can't acquire it through the app store, as every developer must have a developers license, meet Apples standards, have each app they create submitted to and then approved by Apple. So if you seek out this virus, commit yourself to installing it, the uninstall is entirely different then Windows. Where a Windows virus isn't local, it spreads out and infects many things, OS X programs are self contained and you simply uninstall the malicious application. Done, that easy. As well, software updates to the OS do have security updates, which I've seen resolve viruses in as little as a week of them having been created. This scenario is very uncommon, I've seen thousands of Apple computers with maybe 3 viruses amongst them, and I know you will try to convince yourself you are the exception to the rule, or better to be safe, if you really want to throw your money at someone that's useless (like Norton or Kaspersky) just give me your 20 dollars a year, and I"m still cheaper then those worthless programs that will only occupy your systems resources.