What cables are you using for a hidden in wall clean look? I have B&W 802 D3s coming.

I'm using the AntiCables too, except they are run under the floor instead of in the wall.  There is an open entry way right between the speakers, so my options were to run the cables on top of the floor and put some kind of cable protector over them, or run them under.  Since it's a suspended floor, it was pretty easy to drill some small holes and push the non-jacketed AntiCables through them.  No spades or bananas, just the bare wire ends into the speakers and amp.  Works well.  I'm not sure if there are code requirements for "under the floor" installations as there are for in-wall applications, but since the cable is not enclosed by sheetrock and is hanging in free air underneath the floor rafters, I'm not too worried about it.

@bcowen  My understanding about "plenum rated" cables is that code has to do with a fire combusting the insulation and thereby creating toxic smoke. The AntiCables seem to not fall into that category, but they are not plenum rated nor are they designed for that. 

@Vicweast   Thanks!  Haven't ever looked at the code or requirements, so that's good to know.

Is plenum rated that important for in wall speaker cables? 

@mgould This is one link: http://www.bluejeanscable.com/articles/inwallrating.htm

Here are a few quotes from that link:
"The main purpose of NEC is to prevent hazards to human health and safety from wiring, and these fall primarily in a few categories: electrical shock, tendency to start or perpetuate a fire, and production of toxic fumes when exposed to fire."

"To classify the types of cables suitable for reducing these risks in various applications, the NEC provides a system of ratings of cables. An example would be CL3, or "Class 3," which many people recognize as an "in-wall" rating because of the labeling on the spools of speaker wire found at home improvement stores."

"A "plenum," under Article 100 of NEC, is "a compartment or chamber to which one or more air ducts are connected and that forms part of the air distribution system." The most common "plenum" space one sees in a/v installations is a dropped ceiling space in a commercial building, being used as a ventilation return. Most residences do not have any significant plenum spaces, so this is rarely a consideration in a residential installation--but on occasion it can be. Plenum cables are required to have jackets and dielectrics which don't easily give off toxic fumes when burned--the reason being that a fire in one part of the building can, through the ventilation system, feed toxic fumes to the entire building."

...It is a good article if you are detail oriented.  And, it's always good to understand what is involved when you are "breaking the rules" (as in the electrical code etc). I have previously run speaker cables under the floor from an amp to speakers, but that was a long time ago in terms of where my knowledge is today. For a casual space, I'd run cables behind the scenes. For a critical listening set up: No way, out in the open and away from any other cables etc.