
After having a lot of issues with BOClean, I came to the conclusion that the issues it creates far outweigh the potential advantages. Now I just run Comodo Antiivirus, Comodo Firewall and Spyware Terminator (on-demand scanning only). Running a scheduled weekly Spyware Terminator full scan finds the occasional tracking cookie, which could be eliminated by adding the spyware domains to the CFP block list. I also use Firefox, which can be very granular as to what cookies are allowed and denied.
If you're willing to pay for an Anti-Spyware product, Webroot SpySweeper is what I would recommend. Even works with Vista, if you're stuck with it.