Because it's my job to deal with network security, and I like to play with HW/SW, I use an old Pentium box running Linux and various firewall software/proxy tools. For the less geek-inclined, I have been recommending the Linksys router to anyone who can use it, though many xDSL services only offer routers that have to be directly attached to a PC. If you can't use a router/firewall, Norton's Personal Firewall isn't impenetrable, but beats leaving the door unlocked and open. I too believe that you have to use a firewall if you have a broadband connection, or even if you leave a 56k dial-up on for long periods of time. Simply assuming that DHCP's changing IP addresses will make you safe is a big mistake. Sadly, we're reaching the point where Anti-virus and Firewall software is as important as the browser or email package.