I've use AVG, Mcfee, Norton, Kaspersky, and now i've been using NoD32 and a custom made firewall that updates from a backlink to most antivirus' virus definitions! Reason i've been using NoD32 is its light-weight and it gets the job done well without dramatically slowing my computer down none what so ever.! The firewall was programmed by me and my friend. Both work great together although i sometimes download others just to scan everything to double check just incase
~- Also Use MalWareBytes!! Great Anti-Virus/ Anti-Malware!!! Used it for 1 years i recommend!!!! -~