I got AVG a few years ago after having copies of Norton fail on me time and time again because I didn't have enough money to buy a new version every year. After one of my last virus memory wipes I was suggest AVG by some friends of mine on a forum. I'm usually sceptical of freeware so I asked some peoples oppinions of it and did some online looking. At the end I decided why not the worst that will happen is I'll have to reinstall Windows.....AGAIN.
Downloading it took no time at all and the installation was a breeze. I searched for updates right then and set it to auto install updates which it does every morning when I turn my computer on. I have only had one problem since then with a virus and that was a Vundo which I had to install a different program for. I was lucky enough that AVG did catch it though.
Since then I don't worry about worms or viruses because I know AVG can handle it. All I have to do is keep it up to date on the definitions. It has an internal virus database, scheduler, resident shield, virus vault, update manager, shell extensions and an e-mail scanner. That's quite a bit for it being absoultley free.
They do have security sweets that you can pay for but this works for me just fine. If I ever did need to buy software I would buy the AVG out right. It is way better then Norton and Mcafee in my opinion.