Instead of a dedicated server, use a router that can run DD-WRT or Tomato. I use a cheap(35$) refurbished wireless router from Linksys[1] and I am sure there are other models. These will be more energy efficient and easier to maintain than running a dedicated server. Additionally, of course, you can use these as routers for your home network.

[1] http://www.amazon.com/Cisco-Linksys-WRT160N-RM-Refurbished-W...