The best anti-malware applications are only as good as the definitions are current because new threats appear daily. Keeping up-to-date, either automatically or manually, then, is essential for your computer's security. Making a schedule of routine maintenance, and following it, is important. This includes a thorough scan of your computer's hard drive in addition to whatever real-time protection your arsenal of applications affords.
At the present, there is no universal and clear definition of what constitutes spyware; each company has slightly different criteria, and their applications will therefore look for different things. Having at least two of the better products increases the chance that spyware on your hard drive will be detected.
Here is the breakdown of what you need:
1. One AV with real time protection
2. One firewall
3. At least two anti-spyware applications. Depending on your configuration, you may elect to have both provide real-time protection, or just one of them (the other should be scheduled for a manual scan).
4. All Microsoft critical updates should be installed.
I would only add that using Firefox and Thunderbird inherently increase your computer's security.
Hope this helps.
Edited by jgweed, 05 October 2007 - 07:26 AM.