The most recent Windows Secrets Newsletter reported that AdAware and SpyBot (a combination often recommended as the best way to deal with spyware) still miss most of the malware on a system. I've cut and paste a little bit of the article below but you can read the full thing at
http://www.windowssecrets.com/050127/
I'm not sure what to make of this, but there is a follow up article at
http://www.windowssecrets.com/050210/ which seems to underline their case.
I've generally found Windows Secrets to be worth reading - perhaps there is a place for a thread on good PC mailing lists.
Anti-adware misses most malware
By Brian Livingston
Now that 80% of home PCs in the U.S. are infected with adware and spyware, according to one study, it turns out that nearly every anti-adware application on the market catches less than half of the bad stuff.
That's the conclusion of a remarkably comprehensive series of anti-adware tests conducted recently by Eric Howes, an instructor at the University of Illinois.
Howes, a well-known researcher among PC security professionals, collected 20 different anti-adware applications. He then infected a fresh install of Windows 2000 SP4 and Office 2000 SP3 with several dozen adware programs in separate stages. Finally, he counted how many active adware components were removed by each anti-adware product...