there was a thread on this recently.
IIRC Saint Steve (who works in AV) mentioned that HDMI cables are built to a standard, and for non-professional use any cable will do. usually non-branded PS3 ones from HMV and the like are cheap (or at least they were when i bought mine years ago) and they've served me well including 3 house moves/changing set ups etc with no issues whatsoever. in fact i'm using it to type to you now (my PC is hooked up to my TV via the aforementioned HDMI cable).