I don't mean to step on anyone's toes, if I do, my apology...
Camorra a little while ago a double blind listening test was conducted using some sophisticated switching gear to isolate the conductors of each speaker wire being tested. Expensive speaker cables costing several hundred dollars per 3-meter cable were tested against some basic AWG 12, multi-strand lamp cord and some solid steel coat hangers. The speakers used were very expensive, high end. No one could tell any difference in the sound quality between any of those speaker wires. I think using solid steel coat hangers for speaker wire really drives the point home. You can spend as much money as you have on speaker wire, but you cant improve the quality of the sound. Other will disagree and I support their disagreement.
I think if a person claims to hear a difference between the speakers wires, then they do hear a difference, regardless of any actual existence of a diff or not. The brain is tremendously powerful at using personal bias to color reality, so why fight it. I think everyone should do whatever they need to do to get what they perceive as the best sound quality from their kit, and thus the most enjoyment.
Something else to keep in mind is the suggestion that some percentage of your kits cost should be spent on speaker/interconnect cabling. It has no merit except for those that sell such cables and wires. On this side of the pond I have also heard 15% and 20% of the kits cost used as references by sellers of cabling. I am a capitalist pig at heart, so Im ok with whatever someone wants to spend on their cabling, but and Im equally as ok with DIY.
I have a hard time spending more that $0.25/ft for any speaker cable I dont have to walk on. Right now I am using Canare StarQuad 4S11 only because of the way it is constructed. We can walk on it without damaging it. But when I get around to burying wires in the wall I will use Beldin 5000UE. If it matters to anyone, my HT kit is close to $20k USD. What's the Brit equiv, about £3?
Canare StarQuad 4S11 (AWG 14 x 4) $0.63/ft - heavy cable, not recommened unless bi-amp'ing.
Beldin 5T00UP (AWG 10 x 2) $0.27/ft - for those that insist on a 10 gage wire.
Beldin 5000UE (AWG 12 x 2) $0.19/ft - my personal choice.
Prices listed are typical for over here.