The best AV...
... is VirusTotal (http://www.virustotal.com/), and a good backup software in case of infection.
I have a PC since 1991, WITHOUT any AV, WITHOUT any firewall, and NO spreading infection so far (on Win95/98 and now W2K). And still, I used to visit sites like astalavista.box.sk. How? I know my PC very well, detect all strange behaviours, and in particular avoid running any strange exe. It's only since the last 2 years that I'm much more careful due to explosion of malware, and hence I use VirusTotal much more often, but only on files that I decide to scan. I won't let a stupid AV scanning a file that I know for sure it is clean since it is on my PC for years !
AV SW DON'T HELP YOU! They simply fuck up your PC, turning your superb ferrari into a 2CV ! AV are actually the only true viruses on earth, and you ought to pay for it??? What a joke!
I had an infection on the PC on my wife, however protected by commercial AV. An unfortunate visit on a underground cracking site triggered an exploit on IE. Javascript error, with strange title in the windows. Then few sec later, WinXP telling me that PC is at risk because FW was turned off. Then a strange icon on the desktop of a malware detection software that was not installed on the PC before. The app launched automatically, telling me the PC was infected with more > 50 adware, viruses, ... All this in less than 15-30 sec !!!
I shut off the PC, pull the network plug. Restarted the PC, and run the AV. He detected ~20 virus. By comparing the new files on the PC, I noticed there was at least 50 new files that was created in the last minutes before shut off, and the AV only detected LESS THAN 50%. I copied those files to my own PC, and run a online AV scanner on it. The online scanner detected 90% of the files. Two days later, I rescanned the files, 95% was detected online.
The PC was completely unrecoverable !!! How would you trust any AV to correctly clean the machine, when YOU CAN SIMPLY BACKUP-RESTORE IT very easily, with 100% confidence on the result ???
If you understand computer a bit, you don't need AV ! AV simply sucks the power of your PC, continuously scanning and rescanning over and over the same files again and again. I doesn't make sense. Backup-restore and common sense is the best answer. AV are for neophytes and for company PCs only, and yet...