http://spywarewarrior.com/asw-test-guide.htm

It's a good overview of anti- spyware and adware programs. Looks to me like no two programs catch enough of this stuff to be certain of the results. I had little opinion about the MS purchase of Giant until I read this. It looks like MS bought a good company that was doing a good job of catching stuff the other companies were missing

I got the link above from http://www.grc.com/default.htm