Well as an audio engineer, I feel I should throw my hat in the ring again here, referring to the original poster.
First off, I love this place, it provides a heady mixture of entertainment, knowledge and moments of hilarity while scoring relatively low on the troll factor.
The comments at the start of this post where both intelligent and well put, let down only by the "backhander" remark (sic).
Now to business.
When it comes to analogue signals such as line outs, speaker signals, antenn‘, etc, cable quality is paramount. Poorly made cables are usually poorly shielded which simply invites interference and induction problems.
Anyone with good hearing can clearly tell the difference between using bell wire and Monster Cable for your speaker runs.
However, when using digital connections, as long as there is a good solid electrical connection and the cable run does not exceed the specification limit, I've yet to notice any difference in "digital quality" so to speak.
Again, as long as the digital cable is well screened and not damaged, then everything should be fine.
Digital processing is a complex subject and is the topic of many a debate, only last week I was involved in a heated discussion around BluRay and CD players.
Yes they are all essentially computers reading pits off a disc but there are vast differences in quality there too.
Superior electronics and mechanics in players will extract the original data more accurately from the disc and therefore less error correction will be applied, resulting in a truer audio/video reproduction.
In my home entertainment system, I use solidly built £20 HDMI cables and when I had the opportunity to borrow a really expensive set, saw no difference whatsoever.
And I'm uber-critical.
Does a turntable supported by legs that are floating in a bath of mercury really sound better than a well engineered transcription deck on a solid base costing a fraction of the price?
If the difference even was discernable, would it be worth the several thousand pound premium?
Did you really hear the difference between M.Jackson's gold edition CDs and the standard silver ones?
To sum up, in my experience, using cables costing hundreds of pound per metre offer little or no advantage over your average well built cable, especially when you consider what's connected to both ends of it.
The components that come directly before and after the cable will affect the outcome to a much greater degree.
But as people have commented previously, you pays your money and you takes your choice.
For the record, What HiFi is essential, no, required reading in my profession and we've always found it offers a well researched and balanced source of news and information. Keep up the good work guys and don't feed the trolls! ;-)
Flame on . . . .