Posted 22 January 2012 - 11:54 AM
Okay, so here's the thing: Some years back, when anti-spyware with real time protection was popular, the AV programs were pretty basic and, as the title suggests, mainly concentrated on protecting against viruses. So, an accompanying anti-spyware program was nigh on a must. Over the years, and in line with the expanding proliferation of spyware threats, AVs have gradually improved and widened their scope of protection. The modern AV is much more versatile than it used to be and also more adept at protecting against a wider variety of threats, including spyware/trojans. So the necessity for one to augment their security with dedicated real time anti-spyware has diminished exponentially.
Most security experts agree that in today's threat landscape HIPS or heuristic based software, that is software which does not rely on traditional definition data bases but rather on behavioral patterns, is a more effective way to add that second layer of protection to one's security. A HIPS based component is included in most respectable firewalls, Threatfire from PC Tools is one of the better and most popular dedicated HIPS based programs. Windows Defender does rely somewhat on definitions but it also includes a very good heuristics engine - areas which WD monitors for possible malicious behavior include: Auto Start, System Configuration (settings), Internet Explorer, Services and Drivers, Application Execution, Application Registrations, 3rd Party Software.
In terms of augmenting an existing AV with free extra protection Windows Defender is arguably one of the best around. WD does not necessarily offer better protection than firewalls or something like Threatfire, but WD works straight out of the box (no tricky configuration), is very easy to use, updates regularly and is light on system resources - advantages that most of the alternatives cannot claim.