I have a VDSL a connection coming into the house on one side of the living room, and the modem and router sit on top of a tall bookcase directly above where the line comes up through the floor. This works great for the internal wireless network because it's almost in the dead centre of the 2-storey house, and all the cables are hidden behind the bookcase. My entertainment hub is the other side of the room, with no easy way of running Ethernet cables inside the room to the Apple TV, PS3, and planned HTPC. They work okay on wireless, but I'd like to cable them for optimal speeds.

It wouldn't be too hard to get someone in to run a line from the router down behind the bookcase, down through the floor, across the carport ceiling, and back up through the floor to emerge behind the TV cabinet. What do I need to do from there? Can I have one line from the modem, and then some sort of hub or switch into which all the devices will plug? Or do I need to run three lines from the modem to go into each different device? I would be unlikely to be using the Internet connection on two devices simultaneously.