At first look, the word AVG "FREE" make it sounds like unreliable thing to use, but after couple of months of using and testing it's limit into various situation, my netbook's performance is still in a very minty condition...
I downloaded AVG Free from cnet's website ( http://download.cnet.com/AVG-Anti-Virus-Free-Edition/3000-2239_4-10320142.html ) after a couple of minutes of successful installation, I now have an updated protection from Virus Threat and Spywares., plus a linkScanner "as they call it" to ensure the website your visiting is safe... Those are the only features included on the Free version; and because it's free some other good features are locked BUT it doesn't mean your not safe anymore. Well, if you only use your laptop or desktop at home then AVG Free should enough for you but if its for important business work file your dealing with then you better invest on the full version.
Using this Antivirus really makes me feel safe whether your surfing or transferring file, or even inserting USB Flashdrives which happens to be most of the reason why I'm always formatting my system before; but for this thing, It really is doing a great job in protecting my system...
Good Job!