I gotta say that power cords in the open drive me nuts. And that also applies to TV and stereo equipment and speaker wire (yep, I want that "magazine" look).
What I do is hide them between the sheet rock in the walls. Exterior walls are a bit harder then interior ones and going around corners is a major pain. If you want to string speaker wire across the room from the amplifier, going through the attic is a shortcut, depending on the house. I cover the holes in the walls with plastic caps used for wire management in computer tables. They are cheap, come in multiple colors and diameters. There are also wall plates that have a string / pull inside that connects to the cord / wire, if you ever need to un-plug the appliance. In the end, no wires anywhere (and your walls resemble swiss cheese).
Best done by an electrician.
Do share your cable hiding tricks.