The latest (November 2005) edition of the UK magazine Personal Computer World
http://www.pcw.co.uk has a review of anti-spyware. Very briefly:
Two main recommendations -
Microsoft Antispyware Beta
http://www.microsoft.com/ukStill a beta, but ore successful than most, and worth the free download
PCTools Spyware Doctor
http://www.pctools.comGood performance, informative results, free: PCW said there was little reason to upgrade from the free version (to paid-for support). You need free registration for real time monitoring.
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Spybot Search and Destroy
http://www.spybot.infoFree, quick, useful information but doesn't fix everything
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They thought Lavasoft Adaware disappointing for a well-known package. 8 others included in the review.