Welcome to the forum Oorhoose, (would that be "in the middle o' oor street", just oot ae intrist?!
) you've opened up a minefield there. Some will view it as the opportunity to spend a hefty sum, others will go for a less expensive option but which does as good a job.
I have used Audioquest Type IV biwire, had it for about 13 years now in my system. It's a single core copper cable, was about a fiver a metre (think it's gone up a bit over the years, but still affordable) and I use it in two 5m runs. Not that my speakers are 5m away from the amp, but there've been times when it's been close.
Another school of thought will point you towards checking out the resistance of the wire in relation to speaker impedance (ref: Roger Russell, ex-McIntosh, who themselves turn out some very high end kit), and this takes wire thickness and its corresponding "gauging" into account. Probably best to refer to some online accounts behind this rationale, though that provided by both Blue Jeans Cable in the US and Roger Russell's own site are both good starting points, if a little tech heavy.
I would caveat against spending a fortune on cable, both speaker and interconnect. You needn't do this and a little wising up on what counts beforehand will reap greater rewards in the long run. My own spend on interconnects have gone from near £100 down to £7 and I'm currently using the latter with no drop in performance.
Facebook
Twitter
Instagram