PeerGuardian is excelent. I cannot stress that enough. SpyBot S&D and SpyDoctor both do a fantastic job. Ad-Aware is also a good 3rd party adware remover, and comes with a "real-time"scanner also. But for that function you must have the Pro version. And the Pro version isn't free.
CA Anti-Virus and CA anti-Spyware are also great. But DO NOT install the suite. It is worse than Norton.
"Three o'clock is always too late or too early for anything you want to do."