Most free virusscanners catch all (normal) virusses by now. The only way the expensive guys can distuingish themselves is by adding a ton of features (internet filters, bad spyware blockers) nobody ever wanted or needed and by using slicker interfaces (they also bring your system to a halt doing so )
One of the most important differences between virusscanners is the abillity to scan inside different compressed files (example: most scan zip-files but not all can scan rar-files). If you are just carefull and scan again after extraction you should be fine.
In recent tests the big boys did not do very well, their responses to new virusses (database updates) are not very fast, recovery tools for XP that cannot read NTFS and lots of other minor flaws. Not very acceptable for programs that will cost you about 50$ a year :angry:
ive decided that AVG SUCKS. i got infected with some killer virus that reset my pc, didnt allow me to run any exe's and destroyed my drivers. it managed to find it AFTER the damage has be done so i had to do a fuckin system restore. thanks avg
Common sense... it's free powerful and i've been using it for more than 6 years now and never got caught by a virus.
As a side note I want to ad that I've been using the ultra secure Opera Browser for also 6 years now (no opera doesn't come with common sense) and have been firewalled (hardware) since the first time I went on internet.