Kaspersky is supposed to be good, fast and cheap too.
By the way, for those worried with possible infections in IE (undoubtly, the most vulnerable browser available out there) and that PP is supposed to work only in IE, I should recommend you using Opera. PP works fine and its a nice browser. Ive been using it for as long as I can remember. And its fairly immune to web based attacks programmed for IE, as far as I remember, ive never been infected that way.