I also forgot to mention that I was a bit surprised to find the firewall was set to accept all incoming connections, although I'm sure my Panther was set to allow only some limited set of ports.
I'm very happy I'm behind a wireless NAT router using WPA.
If I set up my own firewall rules with ipfw, I wonder if Leopard's firewall will get upset with it. In Panther the firewall System Prefs was all grayed out when I had custom ipfw rules. Only after removing my own rules could I use Panther's System Prefs to e.g. allow access to Apple file sharing.