I'm referring to Zone Alarm, Black Ice, Norton Internet Security, and other firewall programs.  I realize that this sounds very unconventional.  "But Van, are you crazy?  I need my personal firewall to protect my computer from hackers and worms!".  Let me explain myself.

You definitely need protection for your computer from direct invasion by hackers and viruses.  Software-based firewalls do a decent job at this.  However, I've see a lot of cases where the firewall software interfered with the operation of normal applications to various degrees.  In some of the worse cases, the firewall software had stopped the antivirus software from updating itself or had actually causes the computer to become unstable.

With firewall software, the battle is fought on your computer using software on your computer.  The incoming packets have to be received into your computer and analyzed by the firewall software in order determine whether the incoming traffic is bad or not.  This slows your computer down because it uses your processor and RAM. 

With a NAT router, the battle is fought "overseas".  The incoming packets never reach your computer because they are stopped at the router.  This puts no burden whatsoever on your computer.  This is the "George Bush" approach to handling firewalls.

Firewall software also makes it tougher to share files amongst your own computers where the NAT router has no negative effect on file sharing.

What if a user uses a dial-up Internet connection with a modem instead of high-speed Internet connection through a network card?  This will make is tougher to use a router.  There are a couple of options here.  If the user has Windows XP, he/she can enable the built-in firewall on the dial-up connection and this will do a decent job.  Another option is that the some of the SMC Barricade routers have the capability of connecting to the Internet using an external modem.  I've used the SMC Barricade with an external modem many times for an Internet connection and it works well.

One advantage that a software-based firewall has is that it will stop a worm that has gotten into your computer from getting back out spreading to other computers.  If your computer gets infected with a worm, the NAT firewall won't stop it from spreading from other computers.  This is a minor inconvenience as far as I'm concerned.  Make sure that you keep your antivirus software up-to-date and don't open any suspicious email attachments and you won't get infected with a worm, so this will be a non-issue.

So, you can uninstall that firewall software and save your computer a lot of grief and make it run faster.  Now having said all of this, don't uninstall your firewall software until you have a NAT router in place!