Security should be built into the core of the operating system. That's why Borepatch gets on his soapbox ringing the bell and hollering, "LINUX!, LINUX, LINUX!" every time we talk about this. Perhaps so, but it's still a Windows world and I venture that most of you are running some version of it to read this. So anti-virus and security are an afterthought, bolted onto the system like an 8-Trak player in a '69 Chevelle.
Knowing that, what do you use? I use my common sense. I make regular data backups. I stay out the back alley websites. I don't use torrent software. I don't expect anything to be free. I know I am not the millionth viSiToR! and therefore I don't click the banner ad. I don't load helper apps and toolbars in my browser. I don't open attachments in email, even from people I know, unless I am expecting them.
And for software, at home I run Avast anti-virus, MalwareBytes, and CCleaner. There are free and paid versions. I bought a router with some firewall type protections and run my computers behind that.I have explored Windows settings and shut off certain ports. I keep important stuff in encrypted folders that I have to open with a password when I use them.
None of this protects me. Don't count on software to protect your computer any more than you count on the safety on your pistol. You may use them both, and I recommend it, but you should never expect that they won't both fail.