I too have been troubled by the justification for spending large sums of money on power cables, when often a bit of cable management will be more productive. I do run a dedicated ring main to my components and utilise a filter - all of which makes perfect sense.
As regards the mains cables (about �85 a pop) I was fortunate enough to meet a gentleman today who is a recording engineer at Abbey Road Studios, with 35 years experience to hand.
The majority of his equipment at home is Meridian and the power cables are also Meridian. His views on expensive mains cables, which also applied to digital cables, were that they are a waste of money.
Now, having engineered many of the most acclaimed classical recordings in one of the best environments, my guess is that he knows what it should sound like. If his trained ear can't detect worthwhile improvement in expensive mains cables, mine certainly won't.
On the other hand, if I had spent �100s on replacement cables, I might yet convince myself that there was an improvement.
The supplied Meridian cable is a good cable. Could it be that anything else is perhaps excessive. Personally I am saving my money for an HD DVD transport when they finally arrive.