Point of possible interest: The Norton Internet Security that I use permits one "license" to be used on up to three computers.

In our case, it's two desktops and a laptop, connected via a Belkin router and Motorola DSL modem. (A third desktop on the same router/modem setup has its own AV.)

Norton makes it a little "less than obvious" that the license covers more than one machine when you log in for your annual renewal, but that's what it said on the box it came in, and I did once find someone at Norton who figured out that it's true.

The newer Norton 360 is said to be a little faster on scans than what we're using, and the upcoming (possibly available now) next version tracks what your setup is, and perhaps your "exposure habits," to compare your risk with others with similar setup and use, and scans only where intrusion/malware has been found among other "users like you," thus reducing scan times - in the words of several beta reviewers - spectacularly. Of course if there's a question, it will still run the full system scan - which takes the expected "a little longer."

Although the router does have a built-in firewall, Norton still occasionally detects "intrusion attempts," so I've prefered to keep the separate AV Suite on each machine on our little LAN. Some claim that multiple layers of protection on the same LAN can cause "conflicts" but we've seen none, with Belkin, Motorola, Norton, our ISP, and Microsoft all competing to keep us "safe."

A good suite also offers some inhibition against the "phishing" attacks that are the most common form of malware now, while the router firewall alone doesn't offer much in that arena.

John