Nice diagram there. Mine would be similar, same number of computers connecting to the Internet via a router but all them connected by wire to a router. This includes 3 desktops and a laptop. The laptop has been used wirelessly but is currently connected by Cat5 cable to the router, like the desktops.
Have you ever thought about adding print server to the network? It would connect to the router and the printer would be connected to it. That way, no individual computer must running in order for any other computer to use the printer.