Spanky new virus scanners no longer cutting it.

[Lella]

Even users running up-to-date anti-virus software still get infected with malware, according to stats from an online malware scanning service. Nearly a third (25,000 out of 78,800) of computers with up-to-date anti-virus software were discovered to be infected with malicious code when users scanned their PC using SurfRight's HitmanPro 3 behavioural scan. SurfRight's analysis (pdf) is based on 107,435 users who put their PC through its scanner between 10 October and 4 December 2009. Around a quarter of these users (28,608) either had no scanner installed or were running security software that was out of date.

http://www.theregister.co.uk/2010/02/08/security_scanner_shortcomings/