merge posts so this one will stand but thanks for explaining why it was started.
One topic people tend to forget is that you may have a visitor asking you to hook up his laptop to your network to check webmail. But... if his PC has a virus or trojan this will attack your network from the inside! So, I use both the hardware firewall on the router plus one software firewall on each connected PC that monitors both incoming and outgoing traffic.
This situation is also valid if you have your wireless router open so that the neighbor can use your cable or ADSL network...
In order to know how much system resources are eaten by your firewall, press Ctrl-Shift-Esc and choose the "Processes" tab. In my case Sygate (smc.exe) take around 8M; compare this to my McAfee virusscanner that takes around 25M!
Tinus van de Wouw - The Netherlands