Cable Costs Relative to System


Since making a spread sheet with my audio system prices, I have been thinking(shocked) about my total investment in cables. My total system retails at $67,000 (Digital and analog front ends included). I purchased all of it here on Audiogon so my investment is about 50%. Of that I have about 10% invested in interconnects and cables and another 10% in Power Cables (Shunyata Hydra included). That's $13,000 worth of wire. I'm starting to question whether it might be more effective to put some of this budget into acitve components. It would take forever to listen to all possible combinations, but would like to hear others experiences with relatively high end systems and cable selection. It would seem to me that the point of diminishing returns would be reached sooner with cables than with speakers and amps. Do most of you follow the 10% "rule" for cabling? How do PCs fit into this rule? Are there any super bargain cables capable of keeping up with highly resolving electronics?
metaphysics
Mitch - Double Barrel is very good and it is step above Satori Shotgun (so I heard). Satori wires look like Teflon isolated strands + one wire consisting of strands of isolated (enamel) magnet wires. I was looking for Silver Reference II ICs (about $450) while I found AZ Absolute 0.5m XLR for $600. I could not refuse that - if I did I would have bad dreams for the rest of my life, I'm sure.
Stringreen makes a good point about no correlation between cost and performance. A lot depends on the equipment and how it reacts to cables. For example, I just changed to an all Linn system and very entry level kimber works much better than the more expensive and exotic Purist cables I used to own. People need to audition and be careful before blowing $$$ on cables they dont need.
There is also the question of the different parameters that you have to put in the equation (ie country of origin, new vs used etc). For example, on the basis of "retail prices" my cabling would be c. 35% of my system's overall value. They come from a US manufacturer, and their prices are much higher here in Europe (vice versa for European cables in the US). I bought all of them used and sometimes at 1/3 or less of their original value - which would drop the overall percentage to under 20%. This is the important factor - what it actually costs you in real terms.
My friend bought Honda Civic and he just loves this car. He believes that there is no correlation at all between performance/quality and the price. I told him that quality difference between Rolls-Royce and his Honda Civic is pretty much the same as between Honda Civic and a Yugo.

Wouldn't you agree that there is SOME correlation between price and sound of cables - or is it completely random and things like purity of metal, capacitance, inductance etc. are not important at all. Can good sounding cable be made of dirtiest, cheapest copper (copper oxide is a semiconductor)?
I find a greater difference between cables and powercords then between components (up to a point). Example I have found a 3k interconnect that makes a greater net difference then going from a 3k pre amp to a 6k pre amp. In fact cables and power cords can allow a system to image in a way that no amount of money spent on electronics can achieve! I'd say 1/3 of a system should be invested in cables. Not sure where the 10% rule came from, but I just don't hear the same improvement between say a 2.5k amp and a 6k amp with cheap cables as when that extra money is spent upgrading the cables. Seeking performance upgrades thru component upgrades is far more expensive then experimenting with cables.