Wireless is definitely an alternative especially if you need to place computers in places where you can't run cable for safety or aestethic reasons. Two issues to consider:
1. Troubleshooting - Tracing down a connectivity problem with wireless connections can be more time consuming because you need to take new environmental issues into account (electrical noise, electrical interference, signal interference, etc.), that usually weren't a factor with a wired connection..
2. Security - With awired solution, the 2 routes into your network are a physical connection and hack-in over the Internet. With a wireless solution, these same 2 methods still exist but a third is now added. Hackers can "drive-by" with a portable scanner connected to a laptop and discover wireless networks and their vulnerabilities.
The hub is also another reasonable alternative (and probably cheaper depending on the number of computers you are adding). BTW, hubs don't come with NAT capabilities, routers do. You don't need NAT unless you don't have any means of getting more IP addresses for your new computers (You may already be using NAT from your server/ router. How are your present computers getting their IP addresses? Are they fixed - assigned byyour ISP, or dynamically-assigned via DHCP by your ISP or internal DHCP?).
Assuming you can clump together the new computers within a reasonable distance from a drop, going the hub route will definitely be cheaper unless the presence of the hub and patch cords presents safety and/or aesthetic issues.
