Honestly, I don't have anything with an active scanner installed.
I use ClamAV to passively scan my PC once a week, but beyond that I'm unprotected. If I download a risky file, I run the file through virustotal or use a Cuckoo Sandbox to test on a virtual machine before installing.
My reasons for this are varied, and I do have other methods of monitoring my system, but I spend a great deal of my time working with viruses and the overwhelming majority of scanners out there (paid and unpaid) are a joke. While some reviews claim AV detection rates of 90% or more, the initial detection rates of newly created viruses is <5%. That's not to say don't use an AV. Focusing more on avoiding risky habits and keeping your software and OS patched will do far more for you than AV software.
As of 2012, one group's research found that the free AV programs Avast and Emsisoft have the highest detection capabilities, but also give a high number of false positives. I've attached their report, if you're interested. They also cover some of the paid antivirus software available