Your current configuration (software + hardware firewall) is not considered as being too overly protected. In fact, it should be 'the' standard in securing computers connected to a broadband ISP.
Your router's built-in firewall is most likely using NAT, which hides your computer's IP address and blocks incoming packets not requested by your PC. What it does NOT do, however, is prevent unauthorized outgoing packets from leaving your PC. This could be caused by spyware somewhere within your PC. But with a software firewall, like Black ICE, unauthorized outgoing packets can be prevented from leaving your PC.
G'day.
I am currently running a billion ADSL 4 port router with a built in firewall. I am also running black ice. I was just wondering is that a bit over the top or not really? I have also noticed that black ice sometimes has a red line running through it, although it is acually running.
Thanks a lot guys.
Justin.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic