Not sure about which antivirus I should use

Free: Avast, Paid: ESET. Imho they're quite good and never had any problems while using these. Or maybe that's because I always do not trust sites I don't know.

I can't tell you which program is the best for you, as everybody has their personal preferences. I personally use avast! but I complement it with Virus total if I download something. But most importantly, your personal brain.exe will protect you better than any anti-virus software ;)

Noscript, Adblock, Brain.exe, Windows Defender/MSE.

1 word: ESET

I use it for 4 years or so and i am clean. It costs me 15 Euros for 3 lisences from local shop per year.

I have been using Comodo, it is free, doesn't kill on resources and is actually pretty good.

Biggest problem I have is when you first install, telling it only to install the AV and not the other security stuff too.

for a free soft - Avast is not so bad, but it's still horrible with false-positives, often removing an object on it's own without asking you and has multiple other problems. Still it will be hell better than AVG.

From paid soft - ESET owns all.

And stay away from Panda. Too heavy

Avast

Avast is my only love :)

I've always like MSE. Free, no annual "renewals", no ads to upgrade to a "better" version, and works great.

The biggest thing you need to worry about is being smart. A basic AV + a router (for the hard firewall) + being smart > any expensive "security suite" that will slow you down.

Been using avast! for quite a while now.

Eset, best possible protection.

'Nuff said

I use avast free and i think it's not so bad

Stay away from Norton too.

After lots of tests, Avast is the free antivirus that i preferred.
It is fast, light and reliable.
In case you choose it, remember to disable that damned pop-up.
Norton is Satan

What about Avira?

AVAST with Malwarebytes are what I've used for years. I did have one of the Big Three paid AV programs and don't really feel I've missed much.

BitDefender (free), nice, works very well, didn't eat up much of my oldish PC :)

Avast is great, I just switched from McAfee after 4 years with that crap :P

Kaspersky

AVAST for life, free or not still the best for me :D

My ISP gave me a free license for the latest Norton, I was shocked. Not only is it using 60% less resources then avast, but it also let me set it up exactly like I wanted to. It was very much improved from their previous products. I saw two people calling it evil allready, but so far it has been problem free for me.

all of them
you can download the virusTotal client that automatically send the hash of your files directly to the site

Avast! free latest + MS Windows Defender + smart use of Internet!