The best is just using you own judgement. I haven't had any antivirus software since I was 10. I never get Virus's.
Every time I run a scan they find all my crack files and stuff and try to get rid of them.

There is no best antivirus. It depends on what you are looking for.
I use EsetNod

Mac user

I've been using NOD32 since quite sometime and it hasn't disappointed me.

I Always come back to AVG Internet Security, never fails and no problem with keys etc...

I use MSE, but it sure as hell isn't the best. The best way to keep safe is with good browsing habits.

I use Eset Nod32 AV and Comodo Firewall..... best combo IMHO.

Best antivirus in my opinion is no antivirus, because with Linux you don't need one.

I believe this is Kaspersky - although I am using Free AVG Anti-Virus and am not complaining

Kaspersky, I've been using it since 2007