I used Malwarebytes and Spybot S&D weekly as on-demand scanners when I had 2009. They never found anything and I never had any problems. My 2009 license just ran out, so I uninstalled 2009, then installed 2010. On the first scan, both Malwarebytes and Spybot found some items.
Spybot found three trojans in the registry. All were .exe files associated with BD according to a quick Google search. Malwarebytes found 11 .exe files in the registry, all of which were associated with BD. I assume these are false positives? I chose to ignore these files in future scans. Is that okay?