What is the best antivirus?

Nod32
Kaspersky
Norton
BitDefender

If you're gonna pay for it "BitDefender" is probably the best, if you're gonna umm not pay for it "Kaspersky."

I'm paying for it.

I have no idea. I use avast though.

NOD32.
Lowest resource usage, in the top five of finding viruses in it's database, and #1 for finding viruses that are not in it's database(ie: brand new viruses that no one knows about yet)
It also can fit a wide range of users, from basic to advanced, with different setting levels.