Better is relative.
I always recommend Avast. It's free, and it works. McAfee, back when I used it, used a lot of memory and slowed down my parents' computer. It also had one feature that is now taken care of by User Account Control.
Based purely on my memory, I say go with Avast.
I find the use of FOSS operating systems to be the best form of antivirus, but if you must use MS Windows, I've heard that AVG Free (as in beer) is top notch.
If it's a Windows machine, I would recommend Microsoft Security Essentials. It's surprisingly good.