I use Audioquest GO-4's for my Vandy Treo's and Ayre monoblocks.
The length is 6 feet.
My dealer, John Rutan, swears by short speaker lengths (As does Ralph Karsten (atmasphere). Anything longer introduces/enhances cable artifacts.
I don't know what your system is besides the AQ cables, but if you have 'good' equipment, and some disposable income, I would suggest buying a pair of AQ William Tell cables.
I heard them at Audioconnection and the difference between the GO-4 and William Tell was amazing- and I am not a cable nut.
They were truly cleaner/clearer. Even the bass was enhanced.
Like I said, I am not a cable enthusiast, but those cables were absolutely amazing. Yes, not inexpensive, but, in my mind, worth the cost.
Bob