For Laptop I use for traveling and for Friends and Family who only use their laptop for surfing,then I use AVG with Windows Defender and every now and again I use the online scanner from ESET to check if I have any virus/Trojans etc to check that the free applications do not pick anything up.
So far It has not given me false positives like some of the others or try to get me to buy the application like some of the other online scanners. I have tried Norton, Mcafee and Kaspersky before and I always had problems with them slowing down my laptop and not picking up or preventing all of the lastest online nasties. The Laptop running AVG with Window defender runs better than having Norton.
Free ESET online scanner. Use Internet Explorer to do the scan as it doesn't work well with other browers.
My main Laptop I use ESET Smart Security 4, light on CPU, I never had a problems and on three year licence , I can always download the lastest version without having to buy the software for the lastest version.