The desktop firewall landscape is changing fast. It's not the need for desktop firewalls -- that hasn't changed at all. Desktop firewall software remains one of the three essential components of robust PC security.

Start with a good antivirus tool to help prevent infections from viruses, worms, Trojans, and the like. Add a good anti-malware tool to help guard against spyware, adware, browser hijackers, and other miscellaneous forms of malware. Now include a good desktop firewall to help prevent unwanted network access to the PC (and its contents and LAN connections), and you will have closed most of the worst vectors for security problems.

Even in instances where a PC is protected by an external firewall, a desktop firewall can help both as a last line of defense from outside attack, and also as a way to guard against unwanted outbound connections, such as those triggered by the covert "phone home" activity of some malicious software. (More info? See: "How Much Protection Is Enough" and " ...The Single-Layer Defense Fallacy" Desktop firewall software truly is a vital tool in keeping PCs safe.

But the desktop firewall software industry is in major flux. Some of it is consolidation: For example, Symantec (makers of the Norton Personal Firewall, among many other security products) recently acquired Sygate (makers of the popular Sygate Personal Firewall, and other products). Computer Associates bought Tiny Software (makers of Tiny Personal Firewall); Kerio has partnered with McAfee for some of its offerings; and has announced it will soon stop distributing its popular free firewall. And so on.

Even without mergers, acquisitions, and partnerships, there's significant change: For instance, ZoneLabs, makers of ZoneAlarm (which almost single-handedly created the category of "desktop firewall"), now offers five distinct products ranging from a relatively basic desktop firewall up to a complex Internet security suite. More info.

Even Microsoft is getting into the act. It's been shipping a basic firewall as part of XP for some years now, and is extending the firewall's features and adding additional security services through its "OneCare Live" product, now in limited public beta.

In short: There's a lot of dust in the air, making the choice of a desktop firewall more complex than ever.

So, to try to help sort things out, I recently asked readers to volunteer their opinions on what the best-available current firewall is. I analyzed the first 500 replies and will present the results below. It's very interesting: I learned of a few firewalls I hadn't heard of before; and also saw some product-usage numbers that were, frankly, surprising.

And, possibly, quite useful: After all, this is a collection of first-hand reports from your fellow-readers -- people like you. It's the kind of information you might get if you sat down with a large group of people who use their PCs in ways similar to the way you use yours. It's as though you have a small army of people testing and trying things on your behalf.

That said, it's also worth pointing out that this kind of data is anecdotal; it's not a review; and not a way to generate statistics that can be projected across the PC-using universe at large. As long as you realize that the data you're about to see is interesting, first-hand reporting from your fellow readers -- no more, no less -- you'll have a good context for understanding it.

Surprises In Store
I expected some spread in the data, but was surprised to discover that readers were using -- and recommending -- some two dozen different types and brands of firewall products! I had expected far fewer.

With this many products in use, no one tool emerged as the majority winner. But two tools did stand out from the rest, garnering a combined total of 70% of the reader recommendations: 43% of the respondents named ZoneAlarm their top choice; 27% named Sygate.

The next group was way behind: The Kerio and Outpost firewalls each got 6% of the vote. Norton Personal Firewall and Windows XP's built-in firewall each got 5%. NetVeda had 2%; Tiny and EZ-Armor each got 1% of the recommendations.

The above adds up to 96% of recommendations. The remaining 4% was scattered through a range of products, including OneCare, Freedom, Filseclab, F-secure, Defender Pro, Jetico, Kapersky, System Mechanic, Trend Micro Internet Security, Webroot, V-Com, AVG (Grisoft), McAfee, Panda, Avast, PC-Cillin, BlackIce, and several different Linux-based firewalls and specialty distributions.

Of course, the raw numbers only tell part of the story. For the rest, I selected one or more representative comments from among the E-mails relating to each recommended product so you could hear from the readers in their own words: