I’ve got loads of HDMI cables hooking up various things, and I completely agree that the expensive ones don’t offer me any better picture/sound (it’s astonishing to see £120 cables being recommended to people in shops when they buy expensive TVs).
One thing I will say though, I’ve bought a couple of really cheap ones in the past and I’ve had problems with the build quality (e.g. the casing round the connectors falling apart). For that reason I’ve stuck to the ones that have the rubber style case coverings rather than really flimsy looking hard plastic ones – they seem to stand up to a bit more abuse (like constantly unplugging from a laptop, kids playing with them or accidentally standing on them etc!).