Avast and most other pure AV no longer provides sufficient protection RE: modern computers, for most of the malware or PUA came from browers, such as XSS vulnerabilities, malformed scripts with trojans or malwares, freewares that came loaded with backdoors, etc.
Gator no longer the biggest talks in town these days, more like wajam, conduit, etc.
in addition to AV subscriptions, I now also install paid versions of malwarebytes to protect both my work machine and my parent's home machine (where my son also uses it to play online games).
all other flavours, I typically install noscript on firefox to filter pop-ups, pop-unders (or overs) and malicious javascripts from coming in from suspicious sites. I only conditionally allow (partially allow) sites that are deemed safe, incl. BITOG.
Q.