I am still on the fence with bi-wire. Some speaker manufacturer's provide for it, some don't. The one's that don't, obviously don't feel the benefits outweigh the effort/cost. Those that do, either believe in it, or just do it to be perceived as better/more high-end, etc.

Although I only own his subwoofer, I think Richard Vandersteen knows what he is doing when it comes to engineering speakers and maximizing value (performance/cost). All but his least expensive speakers are bi-wire only. If you read his web page, he believes the benefit to bi-wiring is that the collapsing magnetic fields from the bass signals in the speaker wires can induce distortion into the higher frequencies. By separating the bass signals from the mids/highs, you greatly reduce that distortion. As such, he only recommends a "shotgun" set-up, with separate runs, physically separated by an inch or two (enough to be out of the collapsing magnetic field).

I currently have my mains shotgunned bi-wired. I haven't gone back and forth to compare. Basically I had an old 15' pair of original Monster, and for free made 2 7.5' pairs. That alone lowered the resistance and capacitance of my cables by a factor or 2, before counting the effects of the 2nd run.

I think people who hear huge differences may have changed speaker wire at the same time. Thus the measurable electrical properties may have changed too. Resistance is only important if it gets too high. For short runs, once you get to 16 or 14 ga, the reduction is resistance makes negligable differences. Capacitance is another story, but all I will say is that it can vary between cables and can account for much of what can be discerned between cables.

In my mind the jury is still out. I think you need a fairly high resolution system to start with. Then maybe A-B differences can be found. Gross differences, to me, imply at least one set of poorly engineered cables with serious design flaws.

Just my $.02.