Klotz LaGrange Guitar Cable 20ft.
Available in straight to straight end connectors and for a $6 upcharge, straight to right-angle end connectors.
(published in "Just Jazz Guitar", Magazine, USA, August 2002):
[...] The top ranked Klotz guitar cable rates a 10 out 10 in this comparison. Its lack of coloration and almost complete neutrality set it apart in the test. The Klotz also behaves well physically by coiling easily and connecting solidly to the guitar and amp. Those of you accustomed to using free guitar cables or those under $10 will think that I'm crazy to think of a $69.95, twenty-foot Klotz as a best buy, but I'll be ordering one as soon as I finish writing this comparison. It will now become my reference of how a guitar cable should sound and perform. [...]