BitDefender has been rated the best anti-virus software of the month. Auto-updates are included and the software has a free edition which can scan up to over 83000 viruses effectively and efficiently. Scans take about 10-30mins.
Pc-cillin 2003 came in second. You can either buy or download free trials It can detect and remove Trojans and viruses, trials are up to 30 days. It has over 1700 virus patterns, but slow when scanning your computer. Scans are about 30-40mins.
Norton Antivirus 2004 came in third, it is one of the best computers. Scans are about 20-50mins.
Panda Antivirus is a recently updated anti-virus and it has is more than enough for users,giving a free scan at their site. Scans are about 20-40mins. Source