Just stick with AntiVir. It's probably the best freebie out there and ranks second only to NOD32 in terms of heuristics. AVG/AVAST ranked lower than 70 percentiles on some tests so I wouldn't switch from AntiVir if I were you. Also if you have some nasty virus problems that you can't seem to get off of your computer try using the NOD32 trial to get rid of them.
