If the signal stays intact from one point to another, there is no degradation of the image. The signal itself can degrade, in purely electrical terms, if at the end of that run the bitstream can be fully and correctly reconstituted, it does not matter what degradation the signal suffered. But when it starts to fail, it starts to fail dramatically. The first sign of an HDMI signal failure is digital dropouts where a pixel or two can't be read. If the cable was made longer, it would then display no image.
That being said, I have bought all of my cables from Monoprice and have had no issues.
[quote name='KMunley']Do you need an extra wire? Just ordered the ps3 yesterday, doesn't it come with an hd wire of some sort?[/QUOTE]
No, it only comes with a composite cable.