Here's an easy way to neatly run A/V cables, data cables or 12V wiring behind a wall. The kit includes everything you need: a hole saw for cutting through drywall or panelling up to 1" thick, a 90" flexible rod with a hook end to simplify the task of fishing cables through the wall cavity, and a pair of grommets to finish the holes.
The hole saw can be operated by hand, or you can remove the plastic handle to use the saw in any drill with a 1/4" hex chuck. The grommets are easy to install or remove; as you turn the screws, 1" support arms clamp against the back side of the drywall, holding the grommet firmly in place.
Cables pass through a 1 1/2" slit in the pliable plastic faceplate, which grips the cords so they won't drop behind the wall. A simple, tidy renovation, well within the skills of most.