You mean you can buy anti-virus protection?
I've never bought any and never done without anti-virus protection.
But I would prefer kaspersky if I bought any.
Trend Micro user here, been using them for years now and very happy with their software. "The best AV" is subjective, for me personally, Trend Micro meets my needs and works flawlessly
I just switched from Kaspersky to G-Data. It's always rated highly on the comparatives list, and it just plain works. It is also so much faster than Kaspersky when scanning. I've used ESET in the past as well, and frankly it was one of the worst experiences I have ever had with software.
So I voted G-Data. If you haven't tried it, you honestly should.
I voted Kaspersky although I can't see the point of paying for an AV when there are quite a few free AV's that are just as good, and probably lighter on resources due to NOT having all the unnecessary bells and whistles, than their pay for counter parts.
Another vote for ESET for me. Does absolutely everything that I need it to do, good protection in the network etc, easy to disable temporarily to allow certain stuff that could be potentially dangerous but I know isn't really.