As others have said, you can either put a channel into the wall and replaster (looks very neat if done properly) or buy some trunking.
Standard electrical trunking will probably look naff in your living room.
I noticed recently that Maplins sell some curved, aesthetically pleasing(!) trunking, for exactly the purpose you have in mind, by the name of "drop down gorgeous". It is available in white, silver and magnolia - or you can paint it to suit your room.