I've had a chance to test 2 different TVs, a Toshiba Regza LCD (42in) and a Samsung Plasma (50in) [pn50b550] with various brand HDMI cables and 2 different game systems. Testing the Xbox 360, both TVs work fine with any old 6 foot HDMI cable connecting them. The PS3 however works fine with any HDMI cable and the Toshiba, but the Samsung has issues.
I've tried the HDMI cable that comes with the Xbox 360 on the Samsung with the PS3 to have failing color saturation, causing poor picture quality in games and videos on the PS3. Then I tried an off brand HDMI cable I purchased from elsewhere that works fine with the Xbox 360, but has a high glitch rate with the PS3 and Samsung. The glitches that occur are intermittent flickers of signal loss at random intervals. I eventually bought a higher quality HDMI cable, gold plated, that seemed to fix the Samsung/PS3 HDMI problem, but it came back recently at less frequent, but random intervals.
If any HDMI cable works with the PS3 and Toshiba LCD TV, while fails on the Samsung Plasma, it could be a compatibility issue with the PS3 or faulty HDMI ports on the TV. Yet, the Xbox 360 handles HDMI well without any glitches or loss of quality. Odd?
I tried the 4 different HDMI ports on the Samsung with the same results, intermittent glitches and quality loss. Toshiba works fine using HDMI with both systems on any cable thrown at it.