Anti-virus software is a scourge that I'd be happy to see disappear. For the most part, its business model is to prey on the ignorant - I can't even count how many times I've been asked why a computer is running slowly, only to discover that there are three or more competing anti-virus products running, every one of them hooked into every single file read or write. Just yesterday I had to turn off Windows Defender real-time scanning, because it had gone out to lunch and leaked memory to the tune of 2.1 GB. Hot garbage.
It seems like the popular thing lately is to bitch and moan and question the morality of using ad-blockers, but using an ad-blocker is the single most important thing you can do to improve security on your machine for the average user. Blocking Flash, or, should you happen to still encounter it, Java, from autoplaying comes in second. Blacklisting SourceForge in your hosts file might be up there, if they are still bundling crapware with the few legitimate downloads that haven't moved elsewhere.