It really is up to ya.
I had Nortons and a virus killed it. It seemed like it worked but when I scanned an Infected test disk it didnt work. Have ya heard of an Anti-virus killer. I tryed Mcfee and the same happend.
I think that all the totally free antivirus is much better than the commercial ones. I tryed them all.
Avast
AGV
Anti-Vir
and a few more.
I think Anti-Vir is totally underated.
People read about the features and compare apples to oranges. All these work in different ways.
Yes Anti-Vir dosent have a email scanner, unless ya have an Email server ya dont really need one with Anti-Vir, cause any virus that gets to memory is detected it will stop it and the attacments will get scanned sooner or later. So It works differently.
Avast and AGV do the automated stuff and Anti-Vir is manual.
But with any of these dont push your luck. Your never 100% safe.
If ya do lots of Email think about gettin a Linux box with Anti-Vir mail server. Its also free for personal use.