Phono plugs or bare wire clamp things on the speakers/amp?
Normally bare wire, in which case a decent thickness copper one will do. You can get EMF (i think it is) shielded which are sposed too be better. But as ever you get what you pay for.
i'm using 79 strand copper speaker cable for mine, clear jacket with white trace line pretty darn good stuff
having just realised what banana plugs are (slaps face after having mucked about with 7 speaker connections on the back of his amp) i can see why they're SUCH a good idea
8 wires per CAT5 (can be doubled over)... pretty high quality stuff .. suitable for use in standard (lowly - amped) speaker kits -- like the Phillips surround set in my house and the 1/2 mile walk to the elec store was just tooooooooo far and we had obtained the latest family guy