Just put Avast on my new laptop. Was using the 60 day free demo of McAfee and with 2 weeks left McAfee popups were becoming more and more obnoxious trying to get me to buy their AV, by saying my demo expired, I was at risk, not protected any longer unless you renew the subscription, etc. So to keep from getting more McAfee SPAM I just dumped McAfee and put Avast in.
Been using Avast with no problems since Sept 2006.
I like Avast but AVG another free AV is ranked just a bit better than Avast.