Whenever I visit a store to buy cabling I'm staggered by the price of some of the offerings. Do people really think that higher price means a better cable or are retailers simply hoping that people don't look a the price tag?
Well, in all the testing I've done, not much at all. You might get a nicer looking cable in a nicer package, but when it comes to doing what the cable is supposed to do, I've never been able to see any difference at all. I've tried my best to see notice the "more vivid colors" or "clearer sound" that the marketing blurb promises, but I've never been able to see or hear any difference, even in blind tests where I've not known what cable was being used.
And this doesn't just apply to HDMI cables. It applies to all cables (such as network cables, monitor cables, USB and Firewire cables) and connectors such as DVI to VGA and DVI to HDMI. A higher price doesn't mean a better product.
In fact, I've spotted a downside to many expensive cables, and that is that the cables themselves are usually thicker and stiffer, and the connectors chunkier. This adds a lot of additional clutter of your PC or media center and makes routing cables more difficult.
Bottom line, save your money and buy the cheap stuff. You won't notice any difference.