I've just got DSL installed and waiting for Nortons to come. Are you using DSL or Cable? Things change so fast anymore an old fart like me is having trouble keeping up. I may have to ask my 14 year old son.
Personally I got fed up with messing with firewalls, I added a router. I wanted to network my PC and notebook anyway. I got a Linksys 4 port router. Super easy to install and use. It has built in security in the hardware. Now my notebook and PC have access to one cable modem. The amount of spam has been greatly reduced, though not totally eliminated.
I am using cable modem with Norton Firewall. Although with Adelphias public financial issues who knows what will happen tomorrow. It looks like the deal with ATT and Comcask is set to go through. That could be interesting.