HDMI cables have created quite a stir in the AV world. It's a new digital format which has incredible capabilities both in the speed in which it can transmit data and the way it transmits data. Gone are the days when you need to ask your technical guru about which cables to use. With HDMI, it's one cable and you're ready to go for just about anything.
However, debt has also sprung up amid enthusiasts and purists with regards to whether or not high end HDMI cables make a difference. The argument is simple: if HDMI is digital, what advantages would high quality HDMI cables bring? Besides, is there any point at all spending money on anything other than the cheapest and most basic cable?
Unfortunately there is no simple answer to this question. Firstly, not all HDMI cables may be compatible or capable for the application. HDMI has only been around a reliably short time, yet at the time of writing we've already had 3 major updates post the initial release: V1.1-1.3. The latest standard alone, V1.3, has already had 3 versions: V1.3 a, b and c. Inevitably, the latest version will cost more than the earlier versions by the very fact that it's newer and up to date. While the version differences in the latter releases may be minimal, it is worth checking if the appliance requires a particular standard. Using a version lower than that required may be detrimental to quality or functionality.
Another consideration is the quality and design of the cable itself. The HDMI signal is in fact, extremely demanding on the cable. With any cable, the longer the run, the better the cable needs to be. In other words, the longer the cable, the more interference and noise is induced into the cable. Cables are manufactured and tested only on the length they are designed. If a short run of cable were to be extended, there is no guarantee that the cable would keep its performance, or in extreme cases, if it would work at all. This means that if a poorly controlled manufacturing / testing process were to be used to produce the cable (eg from low quality brand), then the quality of a cable would certainly make a difference.
The last point to consider is HDMI's built in ability for error correction. It is true that there is some capability for error correction in HDMI's design. However, this does not apply to video or audio. When used with a compatible appliance, the error correction will simply attempt to guess what the signal could have been. This means that errors will still occur if not transmitted correctly. While the probability of errors is certainly reduced with superior design of the HDMI signal, it is by no means error free. A better quality cable would there reduce the chance of this occurring.
In an ideal world, there would be no difference between a quality HDMI cable and an ordinary one. Unfortunately in the real world this is not the case. There are always bad products, good products and better products. The good news is that the difference between the performance of these products is becoming more and more marginal. If you are looking to buy a cable to connect your flat-screen TV, it's definitely worth getting a quality cable. However, there is also no longer any need to go overboard.