As a recording engineer, you'll get the same story when you're looking into microphone and speaker cable. Does it really matter? Well... yes, it does. When you're recording, you should always be mindful of ways to make your source shine better in your finished product, and cables are often overlooked.
What's in a cable?True, there's not a huge fundamental difference in how cable works from the cheap to the expensive. There isn't some magic formula; it's more about the materials that go into the cables, and the level of craftsmanship.
One of the things to look for is good shielding. Most cables use a foil shield, which works very well, but is also prone to internal cracking, which will allow interference. The quality of the metal in the cable makes a huge difference, too. Higher quality means better transmission.
Where To UpgradeIn your home studio, you'll likely have two very important connections. Your microphones to your recording device, and your recording device to your monitors. Those are two very crucial connections, and if possible, you should use the best quality cable you can afford.
Microphones output a very low signal by nature. Using a really high quality cable on your mic connection will allow the best of a bad situation: your low-output mic will give you better definition, more robust frequency extremes (better lows and more highs), and most importantly, remain even truer to the source. This is especially evident when recording acoustic guitars and vocals. If you can only afford a few good cables, keep them around for these purposes, and keep the cheap, generic ones for use on extras like drums and electric guitar amps.
Your monitoring system, as long as it's reasonably accurate, will also benefit greatly from higher quality cables. The same theory holds true in reverse -- monitoring at high quality will allow you to mix the best possible.