See, I wrote the subtitle in all caps. I must be serious. Or have turrets. Terets? Tourettes?
Expensive HDMI cables are the biggest scam going. Seriously, people are ripping you off.
It is physically impossible to get a better picture with a better HDMI cable. No joke, it's actually not possible by the very design of the technology. HDMI cables transmit digital information, that much is obvious, but it's not like a digital stream off a CD player where if you bump it you lose sound.
HDMI data is packetized. Think of this like the cars of a train. Each train car represents a chunk of data being sent from your PS3 or 360 to your TV. Because of the error correction built into the system, it is highly unlikely one of these cars would be lost. Even if it was, it would be impossible to see it. Worst case, a lot of the cars are lost, and then you'll get dropouts of the audio or "sparkles" or dropouts of the video.
Here's the thing, the quality of the cable has almost nothing to do with any of the above happening. And if it did happen, you'd see it instantly.
There are only two states to an HDMI cable: A working cable that is perfect, or a broken cable that is unwatchable. If you have the latter, return it, it's defective.
Over long runs (50 feet or so) then yes, a better made cable is more likely to be able to carry the data. Notice I said better made, not more expensive. A $20 50-foot cable could be better made than an $200 50-foot cable. Sadly, you'll have to get one to try it out and see if it works. For runs of a few feet, get the cheapest cable you can find. If it works, it works perfect. If it doesn't work, return it and get another.
Let me put it another way. I am a hardcore audio and videophile. I have a projector, 110-inch 2.35:1 screen, full 7.1 audio, subs, and so on and I have no problem hooking it all up with $5 HDMI cables. Why? Because they work perfectly and there's no difference with more expensive cables.
So why are they so expensive? Because they can be. Best Buy may only make a few dollars off the $1,000 TV you just bought, but they'll stand to make $50 on that $100 HDMI cable. No joke. That's the nature and the markup of the consumer electronics. And it's an easy sell, "You just spent all that money on an expensive TV, don't you want it to look its best?" Yes, you do. So buy the cheapest HDMI cable you can. Don't pay more than $10 for a 1 meter cable. Even that is too much.
This is true with all TVs, all sources, even 3D. I am not, however, talking about analog cables, speaker cables and that sort of thing. With analog cables, it is possible to get better performance with better cables. Just not with HDMI, it's a different beast.
FWIW, the 1 meter cable in the image above is $1.89 on monoprice.com. I haven't ordered from them, but a few friends have with no complaints. And that's just one place. There are countless others.
Try a cheap cable. It will likely work, and if it works know you're getting the best image possible. How cool is that?