Kaspersky Internet Security Suite seems to be #1 in Asia & part of Europe. It's never failed me and has always been good at finding things others did not.
As for free... Normally what your ISP will provide is OK. Mine offers Norton. They have improved much over the years... Would still avoid McAfee though.
for me Avast!has been the best paid anti-virus that I have used and really like the looks of it; as for free I believe AVG free is a good choice; it's a good balance between speed and system use with a good virus database.
I used to think AVG was good, but recently AVG has been kinda screwy, it Microsoft support basicly blamed most of my problems on AVG updates and AVG in general. I will try Avast later.
Norton, ehh, it was good while it lasted, but being free, you basicly have nothing, having the paid version, its ok, but not the best.
I have been using Kaspersky on a couple machines and bitdefender on some others and they work very well. Stuff occasionally gets through depending on the user but they block most the bad stuff. Sometimes it can't be helped if the user doesn't block something when prompted or if they click on the wrong thing unwittingly starting a virus chain reaction.
I recommend Malwarebytes to compliment the antivirus you choose which is a great free program and helps for machines already infected.
I used to be a large fan of NOD32 but after seeing the other anti-virus advancements and their detection methods I have switched to other anti-viruses.
I have used AVG for a good while, and also Spybot. I cannot give a good opinion on paid virus protection, because I will not pay for virus protection. And really, if someone is going places on the net they shouldn't be, they will probably get a virus whether they have proper protection or not. I think I have seen more people get viruses from Facebook in the past year than any emails. I have had to make runs over to my moms pretty much every few months because she clicks something on Facebook and gets spyware on her computer.