Length and Wire Gauge
In reality, however, you're unlikely run more than a few feet of wiring at a time. For simple home audio setups, 16 or even 14 AWG wiring should suffice. If money isn't an issue, you could go even thicker, but any actual difference is unlikely to be noticeable, except on the best of audiophile gear.
To Shield or Not?
Unlike the wiring included with your headphones or PC speakers, copper speaker wiring carries a very high current and much stronger signal — enough that most sources of noise and interference won't affect the audio signal in any noticeable way. In fact, many audiophiles use shielding, not to protect speaker wire from external interference, but to prevent the speaker wire from interfering with other cables in a home theater setup.
Hooking Up: Choosing Your ConnectorsThough actually deciding on the right style and thickness of wire is important, you're not quite done until you've settled on the proper connectors. Perhaps the simplest method for connection is to use the bare wire endings stripped from the insulating sheath. A bare wire will work just as well as any connector, though it may be susceptible to fraying or breaking over time, particularly if reconnected often.
Have any tips for connecting your own speaker wiring? What length and gauge are you using in your own home audio setup? Be sure to let us know below.
Images via Flickr user fellowapeman, JungSon and Crutchfield Electronics.