A while back someone asked me what was the best software for protecting against spyware or removing it after you get infected. (For a definition of spyware, and other terms used in the article, see Protection Vocabulary 101.)
My answer to the question was basically that it depends on who you ask and when you ask. It seems like every six months there is a new top product to control spyware. That is one of the reasons that Emerson has stuck with the free options rather than buying a product to deploy campuswide. For a while the best options were also the free ones: Ad-Aware SE and Spybot Search & Destroy. But then Webroot Spy Sweeper started getting great reviews, and a few others had their moments.
I came across an article on CNET last week that evaluated the Top 10 antispyware applications. This time, ZoneAlarm Anti-Spyware came out on top with some other new names rounding out the Top 5. It looks like the big AntiVirus companies (McAfee, Symantec, TrendMicro) have caught up to the companies that are just offering spyware protection. One other item of note, Microsoft's Windows Defender has been getting good reviews and is available for free at this time.
The bottom line is that if you are looking to protect your home computer, you should probably buy a security suite that offers AntiVirus, Personal Firewall, Anti-Spyware and possibly Anti-Phishing. You could get all of these with separate pieces of software, but it now looks like you can get the best security for the least hassle in a single box. If you already have some of these, and are looking to add Anti-Spyware, you might want to look at the free options. And who knows, all of this might change again in six months.