Pull off the baseboards, use a router to make a nice groove in the back and run the cables in the groove--this way there is no sheet rock repair. If you do it carefully, you shouldn't even need touch up paint.
advice on hiding cables
My speakers (B&W N804) are up against an 'outside' wall while my system is against aninterior wall. There happens to be a fireplace between the two. I had a tech come look and to run wire hidden in wall would be around $500 - which include sheetrock repair (not crazy about cutting two holes in outside wall due to firebreak in 12' wall). Does anyone have a solution for cable management that would be pleasing to the eye? My speaker cable is 4-14 ga bi-wire (65 strands/wire).