HDMI is the devil.
that being said we're all stuck with it so yeah that's probably the way to go, in fact it's really your only option if you want to watch blu-ray discs.
For audio if you're not using HDMI you can use either Toslink/Optical or you can use a digital audio cable. The nice thing there is if you have the output and input for digital audio on your components you can just use a composite video cable, since the have the same impedance.
As far as brand name cables go, yes I have heard a difference in audio quality when I switched cables. But the difference you hear is also depending on the other components in your system. Personally I think Monster while a decent product is over rated and over priced.