In all honesty, you will not find better than Bit Defender. Install it and forget about it.
http://www.bitdefender.com/solutions/free.html
Bit defender caused all sorts of k@k on my pc, programs stopped running scp Connections becomes a hassle, VMs becomes a problem, don't even let me get started if you have any pirated software, you can forget about it.
Bit defender is good yes, but the amount of effort required to make normal stuff work again is why I went to Eset.