Another good program is Spybot S&D (search and destroy). Besides scanning for known bots, trojans, and sundry, it also has the options for locking your startpage and internet options. If also using Adaware, that program will see the locked start page as a problem, but it's rather easy to add that one to the exclude list.
We use trendmicro's housecall, avg (free standalone virus scanner with boot scan), adaware, and spybot. Coupled with a packet sniffing router, little gets in, except through my SO's email...and those nefarious critters get quickly and automatically quarantined.