Most neutral speaker cable for less than $5 a foot

Extension cord from Home Depot...but whatever you do, don't use the cord with anything else before hooking it to your speakers or it will affect the burn in.

A Hedge trimmer makes the cable sound clipped
A vacuum cleaner makes the cable sound suck (but it can be complementary if you use a tube amp)
A power drill makes the cable sound penetrating

LOL ;-)

Beheme,

I use XLR cables. Ordinary "Yorkville" cables from Long and McQuade (a guitar/music store). The speakers are active and as such have very high input impedance. The XLR cables carry low level signal voltage with very little current and act as long interconnects.

I have used 14 ga orange extension cord for 20 years with various passive speakers with 40' runs (orange is ugly unless you can hide it).

I currently use about 50' of Monster XPNW 16 gauge wire to the passive surrounds. I don't like the way it knicks easily but it is flat and easy to paint.