As a matter of fact, the router/firewall I am currently using is a US Robotics Wireless. I can honestly say the secondary router (firewall or not) will not be wireless. I just think since the prices are so close to get another router w/ firewall is more realistic.

What about this situation:

I have a friend who has a network of five computers in his basement and networked off to one system in the living room, his bedroom, and his roommates room. Since his network comes into a router/firewall and then to a switch to be split thoughout the house. If his roommate wanted to secure his system from the rest or split the connection to more than one computer would they be able to use a firewall/router in the room without any conflict on the primary network?