I use Avast and I've had no problems. I've used McAfee and Norton on previous computers, and all I can say is that those two programs were some of the worst programs I have ever installed. Can't completely remove either of them from your system, they worm their way in much like a virus or spyware would do. My Avast was free and blows both of these programs out of the water.
Just curious though, what happened to the original thread discussing this issue?
P.S. The irony of a pirate using anti-virus software named 'Avast' does not escape me.
Love this program though, it is beyond simple.