I use AVG. I once switched to Avast after hearing a lot of recommendations but found it really slowed my computer down. Ironically, everyone else I know has had the opposite experience. They find Avast faster than AVG.
Initially i was the Quick Heal , then switched to Kaspersky for long , then AVG , BUT now back with Quick Heal...
I have 4 computers at home, and each computer is running on different antivirus program, namely 1 on kaspersky 1 on avast 4.8 1 on AVG 1 on nod32 i can say that kaspersky did improved a lot and it's far one of the best all-protection program that i've used. AVG is free, but sadly, i got so many trojan horses, malware and other spyware which enter my system once in a while. nod32, and avast 4.8 is good, but still i prefer kaspersky though.