For years, I have used McAfee for all of my anti-virus needs. I would like to say that it was because they were the name that I felt that I could trust, but, in truth, I believe that it came with one of my computers. Early on, you would by the software, and then be entitled to updates of the Virus Definition files until a new version of the software came along. But, like other AV products, McAfee implemented an annual subscription based model.
But then, they became much more than Anti Virus: they became a "Security Center." If you did not have all of their products, you were shown as having less than perfect condition by their software. That is, if anything, a power lesson in brand loyalty and simple suggestion that you are not safe.
Something deep inside me got mad. Mad that, before 1995, this was not even a business, and now we have to protect our computers just to check our emails. Then, along came AVG.
Currently at version 7.5, you can download and use for free. It is a full feature Anti Virus Software that automatically updates its virus definitions (also free). If you like the product, you can always purchase the commercial version, but, I think I like this version just fine.