[IncubusSoftware]

Avast Free Antivirus. It just does the best for me and it's way better than the Norton Security Essentials that the guy who gave me my PC put on it.

[Fluxify]

The best anti-virus program is common sense.

[Reiko]

The best anti-virus program is common sense.

Until you get hit with [insert your fav. program] 0day by that guy who hates your face, and realize that malware is not just something you download through your browser.

[Satan]

Toasters don't make sushi.

Apparently if I quote @Reiko this happens. I'm not sure what just happened.
But at his above post, basically that's what usually happens.

The best anti-virus program is common sense.

Common sense? If it were common, less people would be infected by malware, and wouldn't have to use antiviruses.

[w00t]

Until you get hit with [insert your fav. program] 0day by that guy who hates your face, and realize that malware is not just something you download through your browser.

Anti-virus is generally understood to be only designed to prevent passive attacks. If someone has the know-how to leverage a 0day, odds are they know how to get about an AV.

[cr33pyguy]

I believe that F-secure is quite good, however if your subscription ever runs out it turns to something very close to a virus itself.

As multiple people have mentioned, a load of common sense and a functional brain will get you quite far.

[SuperDeath]

Eset and Malwarebytes.
both are really good

[xornull]

Many people would say there isn't much of a difference between anti virus companies, but from what I've discovered just today
there are a few differences to consider when choosing an anti-virus:

A. Time to find malware - the amount of time it takes for a company to find a virus and add it to their database.
if you scan an ancient virus and the AV still says it's clean, then obviously it is not for you.

B. Quality of software - The big part that plays in anti-viruses:
B1: Scanning speed - the amount of time it takes to scan the whole system.
B2: Quality of signatures - how good a signature in a sense that if a file is change it can still recognize it, requiring malware
cod3rz to work a bit harder to change their stuff.
B3: Heuristics - how good an AV is at telling the user if a program might be suspicious, recognizing potential malware behavior
Such as use of URLDownloadToFile, I've noticed that using it on a file that ends with .exe will trigger a detection,
I removed it and simply did a strcat with .exe and tricked most of the AV's into thinking it's clean, this is because
URLDownloadToFile is used often by downloaders/droppers, and executing it afterwards makes it even more suspicious.
B4: CPU usage - when scanning, people should just leave the computer alone so this shouldn't matter, but runtime CPU usage
is what people care about, the amount an antivirus does in runtime is what affects this.
B5: Emulation - emulation is very powerful against oligemorphic/polymorhic engines which causes a lot of trouble, so the
quality of an emulator, how good it is against anti-anti-emulation techniques, factors into this, however it can't go too far
if there is a above average decryptor.

These 2 factors are what is important on anti-viruses and this is all in my opinion.

You don't see these things in those fancy reviews with the 5 stars and the <SECURITY JOURNALISTS/WRITERS> who don't know jack shit and love getting bribed by the AV companies to give them good reviews. many anti-viruses are good and bad at these parts and it's quite funny to see those shiny ads and the papers written by the AVers who act like everything is going well and they are winning the fight.
shit about anything,

anti-viruses are good at getting rid of the common stuff, but the new ones, I don't think so, I would say Kaspersky AV is pretty good, since the owner
found a method to counter polymorphism a decade and a half ago, plus they have good signatures, however in point B3, they failed against my technique.

[Null_Byte]

The best anti-virus program is common sense.

I was going to say this but then I saw it. If you know what you are downloading and looking at, you will not need anti-virus. Now regarding a 1337 h3x0r and his 0day's, honestly you are fucked. Plain and simple.

[Infinity]

Paid: Kaspersky, ESET Nod32

Free: Avast, Avira