Avast Pro Antivirus 5 ($US40 for a single-PC, one-year license as of 11/23/2010) ranks third in our roundup of 2011 paid antivirus products. When PCWorld last looked at Avast's paid antivirus offering, our reviewer wasn't particularly impressed with either its interface or its malware detection capabilities. Avast Antivirus Pro 5, however, is a definite improvement, thanks to a slick new interface and some useful additional features. But middling detection capabilities relative to other paid antivirus software keep it from claiming a higher ranking.