for filesharing apps, see PepiMK's Article (the maker of spybot) for antivirus, i reviewed 11 antivirus products, freeware and non freeware, it includes detection rates and memory usage. Link to Antivirus Review Roundup i would reccomend the freeware antivir, according to spywareinfo, it has a better detection rate than AVG and also does not require you to register it and enter keys like AVG.