I'm sorta new at this, but in my research, (asking questions at BIG stores, and small, private businesses, reading lots of reviews) I've come up with a couple of points of interest. 1. If it sounds good to your ears, it's probably OK to use. (I wasn't too impressed with that answer.) 2. Bigger is better. (From a BIG store with lots of wire stock.) 3. It's the overall resistance from one end of the wire to the other that will make the difference. (That began to make more sense to me.) 4. The signal, or current, travels mostly around the outside of the wire, so the more strands the cable has (more outside surfaces to travel on) could make a bigger difference than the size of the wire (AWG: 18, 14, 12, etc) For shorter runs, up to about 25 ft, 14 guage, multistrand cable will most likely be adequate, unless you have 100's of watts going through the wire. Most moderate listening situations only require a few watts, even if your amp is capable of producing much more, so 14 ga. cable will likely be plenty. (I got this from the small shop, a high quality car stereo installer, and also a Marantz dealer) Also, the quality of the copper is important, but the degree of improvement from high quality (read EXPENSIVE) cable over cheaper, multi-strand cable (e.g. speaker wire from Home Depot...) won't be picked up by most people, only sensitive instruments. If you have a very powerful amplifier (150W plus per channel) and listen to VERY loud levels, than 12 ga. or maybe 10 ga. would be called for.
Personally, I use an inexpensive 14 guage, multistrand speaker cable for my system. I can easily rattle the windows without approaching max volume. I have a Marantz 4500 receiver (80W X 7 channels), and plan to soon upgrade to some Axiom speakers.
