I run Windows Defender & Firewall {Win7}, Avast! Antivirus, Opera with Fanboy's Adblock, NoAds and WOT extentions. I scan about once a week with CCLeaner, Spybot S&D and Malwarebytes. Everything I download gets scanned with Malwarebytes, Avast and VirusTotal.

Beyond that, I use my head. I don't click links willy-nilly. I keep everything updated, I backup my system, and use strong passwords. I use an authenticator, my battlenet email is not used for anything else. I check headers on any email that claims to need something from me.