Thanks for the professional input. This is an old question on the JREF Forum (now International Skeptics Forum) and a great example of practical skepticism.
Sure thing. To be clear, there can be real benefits to laying down extra money on better cable, but the trick is in defining exactly how that cable is "better" and in whether or not those potential benefits are anything you actually care about.
For example, things like what the jacket is made out of, how thick the jacket is, and how the shielding is designed (e.g. braided or spiral unbraided) can have huge impacts on how you deploy a particular cable. If you want to run cable through an air duct or certain other sensitive areas, then you have to used something that's plenum-rated, which means that it's not going to put off noxious gases when it catches fire. If you're working on a concert tour, then you need cables that are durable but that are also very flexible and that lay flat when you coil them. But if you're wiring up a rack or the inside of a console, then durability and pliability aren't big concerns, since nothing will be moved - but cable diameter is a concern, since you need to pack a ton of cabling into a tight space. Small diameter on a concert stage can actually work against you, since the connectors require a jacket diameter of a certain size so that the strain relief has something to grab onto - if it's too small, any tension on the cable will be applied right to the solder joints, making them fail sooner. Braided shielding may offer better RF rejection, but it takes longer to assemble, and if you're paying your bench guys by the hour.... One of the more interesting ones (for me, anyways) is Star Quad cable, which uses a twisted pair for each conductor instead of a single wire. It offers better RF rejection, but at the cost of slightly higher cable capacitance, which causes a small but measurable high-frequency roll-off. It's also kind of a pain in the butt to assemble.
Typically, though, if I'm buying stuff instead of building it myself, I just look at the connectors. There are only a handful of companies that make reliable audio connectors in large numbers. If a cable is built with connectors from one of those manufacturers rather than some Chinese knockoff or (worse) molded plastic, then I can be reasonably confident that, unless I have some really specific and/or heavy-duty requirements, the whole thing is going to be acceptable for my day-to-day stuff.
For the average person at home, there are a ton of things you can do to make your gear and environment sound better (including some that are very effective and relatively inexpensive), and as long as your cables aren't broken, fancy cables are pretty far down the list.
