No, Not all HDMI cables are created equal. However, if you are going ~6ft (like 99% of the HDMI users do), it doesn't make a difference. The only difference is for long runs of cable. Also, if you are running HDMI 1.2 or lower it doesn't matter, but with 1.3 it does. The PS3 is capable of 1.3, but if your TV isn't then you are probably using HDMI 1.2.
However, Price != quality. You can get a quality cable capable of doing HDMI 1.3a in long distances for cheap if you shop in the right places.
Here is a note about cables. This is why I say that distance matters. Shorter cables even if they aren't category 2 certified will work in short runs. However, with the longer runs the capacatance of the cable increases which decreases the performance of the cable. If you need a category 2 cable over a long run, but a category 2 certified cable, otherwise just buy it and test it out and you'll probably be fine.
Recently, HDMI Licensing, LLC announced that cables would be tested as Standard or High-Speed cables.
Standard (or “category 1”) cables have been tested to perform at speeds of 75Mhz, which is the equivalent of a 1080i signal.
High-Speed (or “category 2”) cables have been tested to perform at speeds of 340Mhz, which is the highest bandwidth currently available over an HDMI cable and can successfully handle 1080p signals including those at increased color depths and/or increased refresh rates. High-Speed cables are also able to accommodate higher resolution displays, such as WQXGA cinema monitors (resolution of 2560 x 1600).
It is possible for a cable to pass a 1080p signal and 1.3 extended bandwidth signal without being Category 2. These cables would have bandwidth that are beyond category 1 but below category 2. Most of our non-category 2 cables perform in this range.
