For me Kaspersky is the best. I've used this for so many years and really satisfies me.

Eset nod32

Eset but the best free one is Avast I think

I voted for Avira and Kaspersky - Ive been following all AV testing sites for years and both of these top the charts for overall protection and being the lightest on the system, anyone who says "ahh but avira gets loads of false positives" oviously hasnt been keeping up with recent events, in the latest tests for the past year its only been getting one or two - BitDefender is also an excellent AV/IS but is a bit heavier on the system

best free = AVIRA
best paid = KASPERSKY

I would normally advise to install private firewall alongside Avira Free as this is a top firewall with HIPS (Host Intrusion Protection System) and is extremely light on the system, which comes 2nd to Comodo (but that is system resource heavy, also has load of alerts which can be confusing and annoying)

I use:
Avira (Free)
Private Firewall (free)
WinPatrol (free)
MalwareBytes Anti-Exploit (busy testing this out, also free)

this gives you solid protection all for nothing, ive never had issues with viruses etc

Not sure, maybe NOD, maybe KIS. With all its the same problem with malware for me

Nod32

Nod32 gets my vote.

i use a torrented version of avast serves me well and is usually pretty good at picking up packed virus's

Bitdefender Antivirus is also a good option

I use 360 total security, not to be confused with the other 360 from norton, this one is trhe number one antivirus in china and think its the best free antivirus, has alot of features and a great engine