Looks like Microsoft's AntiSpyware may be as good as the combo of the 2 free programs Spybot Search & Destroy and AdAware, according to this article on Slashdot that links through to this test done on Flexbeta.net (I found all of this at this post on Lockergnome). From the test results:
"Microsoftâs AntiSpyware Beta does an extremely well [sic] job for an application still in beta phase when it comes to detecting and removing spyware/adware; and a nice job when compared to the alternatives such as Ad-Aware and SpyBot S&D. The initial scan brought up a total of 2,404 files infected, 5,902 registry keys infected and 10 memory processes infected. The scan time took a little over 25 minutes to complete."
"...if you chose to use Microsoft AntiSpyware as your spyware removal tool, you will still need to run other tools such as Ad-Aware and SpyBot."
I still like the question posed by Lockergnome:
Is it fair for Microsoft to charge its customers for software that is made necessary by the company's inability - or refusal - to repair the fatally-flawed Internet Explorer?
In my opinion, Microsoft should upgrade Internet Explorer to include the AntiSpyware functionality. I run Spybot S&D and AdAware once a week and they only thing they seem to pick up is a DSO Exploit for Internet Explorer -- I haven't had any real problems since I switched to Firefox as my web browser.