I try to keep my wireless locked down. However, I wonder sometimes if it really matters? The risks that I see are that someone will do something illegal that could get pointed back to me as the ISP will only know about my computer. And, the ISP may think there is too much traffic so might shut me down.

But, is a shared Windows network hiding behind a router at risk? This is a peer to peer workgroup, with the default workgroup name changed to something only I will know about. Assuming that I have the router properly configured (and also have a software firewall), can someone get behind it enough to figure out how to break into the workgroup?