I sincerely hope you are asking for the BEST ANTI-malware software out there!
And the proper answer is: No software at all! (sounds strange?)
No Not really! since the use of an anti-virus software is not equal to SECURITY! (It only ADDS SOME security but it´s not security per se!)
So? What is true security then?
True security is built by making it as hard as possible for both malware and attackers to actually be able to cause damage or to be able to "install" malicious stuff in your computer..
I actually prefer https://home.sophos.com that is free and allows you to control the protection of up to 3 different PC (or Macs) from the same registered account! And you do get 30 days of FREE Premium protection as well!