Any speaker cable's sound quality just blown you away?

Among all of the tons of speaker cable out there, which model has stood out in your mind as the best that you have ever heard, and why? If you remember the audio system (especially the speakers) that you heard them with should prove to me most informative. What was the configuration (i.e. single run, shot-gun, bi-wire, or tri-wire), and the length? We know most are looking for a great cable at a little price, while we all dream of the ultimate cable in our audio system. And with so many companies out there making good stuff, it seems that more offen than not, the best sounding cable, though definitely not the cheapest, is not the most expensive either. What is your experience?