I would agree with the majority of opinions above that speaker cables have a significant impact on the sound of any system, and also that the cost of the cable does not always correlate to the sonic performance of the cable.
I have done some experimenting along the lines of what Newbee describes above, using both stranded and solid core wire of differing sizes, and even some different conductor material. I also tried using each cable type in both a single wire run, and a 2 cable bi-wire (as opposed to an internal bi-wire with one cable).
With each change in cable type, I was able to hear meaningful changes, and with all but a couple of the cable types, I was able to detect a subjective improvement using bi-wire vs. single wire. To me, this experience validated the idea that all speaker cables have an impact on the system sound, some more than others. When all was said and done, I preferred the set-up that I had started with, which was a double bi-wire run of mid-grade Audioquest speaker cable (Crystal). Unfortunately, or maybe fortunately, depending on how you look at it, my budget does not allow for me to compare true reference cables with my current configuration, but I strongly suspect that moving up the food chain would yield some sonic benefits.
Certainly there are many different theories/ideas regarding which design characteristics are most important for a particular type of cable, whether it is an interconnect, speaker cable, or power cable. Unfortunately, many manufacturers of high end cables don't disclose much information about their designs, so it can be difficult to know what you might be getting ahead of time. If an equipment manufacturer is not willing share with their potential customers their design priorities and product features that make their product superior, I usually assume that they have no design priorities or unique product features, and that they are simply trying to sell mediocre crap to un-informed buyers, sometimes at ridiculous prices.
Bottom Line (Since your original question dealt with the cost of speaker cables): Selling price has nothing to do with manufacturing cost or quality. Any product, whether it's a speaker cable or coffee maker, is worth exactly what you can get someone to pay you for it. This makes it particularly difficult to compare cables in the same price range from different manufacturers, because one might be running on thin margins, trying to build their market share, and the other might be sitting on a very small share, but pulling down 80% Gross Margin. In a high volume marketplace, the market forces will eventually "shake out" the scammers that are not providing good value for the dollar. In a niche market like high end audio gear, especially in any type of cables, you will not always get what you pay for.
My recommendation would be to audition some higher end cables from Nordost (to compare directly to what you are familiar with), as well as some upper-middle level cables from some other companies that you consider reputable, and decide what sounds best to you. If you find another cable that you really prefer to the others, try auditioning a couple notches up in their product line to see if you get continued improvement. For instance, maybe a cable with the same construction techniques, but silver conductors instead of copper, etc.. Eventually, you will get to a point where you are satisfied with the sound and you no longer hear a difference between similar models, or you will have reached the top of the product line, and have no more room to upgrade.
On the other hand, if you are satisfied with the sound you have today, it may be best to leave well enough alone.
Sorry to be so long winded,
Mike
