I did some research about this a while ago when I was buying an HD T.V. What i found was that almost all experts agree that there is absolutely no difference between hdmi cables. I won't pretend to be able to fully explain all the science behind it but here is what I found to be the gist.
When cables used to deliver an analog signal, there could be a noticeable difference in quality in audio and video because part of the signal could be lost with cheaper cables. With the digital cables we have now, like hdmi, what is being transferred is binary code. It is all ones and zeros. And those ones and zeroes do not get lost .
The reason that you will see hdmi cables that cost 10 dollars and ones that cost 150 dollars, is that there are people out there who are used to paying more for better cables, and will do so because they want what they think is the best.
Don't be fooled though. Buy the 10 dollar cable and save the rest for a great tv, where there is actually a difference.
I had a wireless router made by belkin that I paid $130 for and every week I was on the phone with tech service and resetting it everyday and certain devices just wouldn't connect to it, meaning I had nothing but problems from it until I just bought a $60 netgear router and haven't had a problem with it for over a year now. When it comes to cables as the poster before me replied, it really makes no difference with video or sound quality in cheap or expensive hdmi cables they serve the exact same function.