How important are speaker cables to the sound emanating from the speakers?

Legacy recommends Morrow cable, and uses Morrow SP7, $1499 a pair, at audio shows. Clearly, while Dudleston might view cables as the the least important part of the playback chain ( and I agree ) he nonetheless finds speakers cables to be very important...

I don't look to professional studio personnel and technicians to know how to set up a fine home audio system. I advise not to listen to them. 
Even the venerated Alan Parsons showed his gross ignorance in this respect, as I commented on years ago. 

Bill Dudleston  at my request  upgraded my Legacy Whisper DSW speakers to "Clarity Edition" as an experiment regarding efficacy of internal speaker wiring. You can read about that also at Dagogo.com. In brief, he also suggested a caps change to Clarity Caps (no relation to Clarity Cables). He wasn't expecting much, but was impressed by a measured 2dB improvement in the bass. Some would suggest neither the caps nor the cables should have made a change. It did, measurably.  :) 

For any naysayers who think that speaker cabling does not have a profound effect on the sound quality of a system, I would recommend trying different brands in ones own system.

 I have found speaker cabling offers a huge increase in quality of sound. If you ever have a chance to listen to Klee Acoustics speaker cabling,please do so...you will be astonished by the overall improvement to your listening experience. Highly-recommended.

That's a great link dsper. I haven't been to Roger's website in years and had forgotten about it.

I especially like this tidbit: "When there is an audible difference in speaker wire due to wire capacitance, it can be interpreted as an improvement when one wire appears to have more clarity but is actually altering the sound and departing from accuracy. "

John Dunlavy was another very credible manufacturer in the high end who also felt the same way. And I've read the same from dozens more over the years. Here's one Dunlavy link: http://www.avsforum.com/forum/28-tweaks-do-yourself/36910-cable-nonsense-john-dunlavy.html

Whether one chooses to believe what these guys say or not, you owe it to yourself to try some blind listening tests. The placebo effect is stronger than anyone wants to believe (check out the Dunlavy link), including myself sometimes, and I have witnessed it firsthand in other listeners literally thousands of times over the years.