Spybot is very good, but you should always have two anti-spyware progs. I suggest adding Ad-Aware SE Personal. Other software you might consider are Zone Alarm (personal firewall), VTE (anti-virus) and Dr. WEB Cure It! (anti-virus and spyware). I'm currently running the latter two to see if they are improvements over what I'm already running.
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"Offer them what they secretly want and they of course immediately become panic-stricken."