As someone who sold said Monster Cables my answer would be.. no.
..but it's a conditional "no".
What speakers are you running? What type of reciever. Most people won't hear an audible differance between the monster standard cables and their high-end cables. My whole system is hooked up with Monster, but I got the crap at 60% off or for free. I even have one of those Clean Power surge protectors, 3 of them.
They can make a differance, but I've noticed the differance between the lower-mid line cables to be 99% of what the high-end delivers.
I think it's all subjective, as someone who would spend $3000 hooking up their system would like to think it all sounds and looks better. In reality I don't think most people would notice a differance.
Just don't use the shit cable and you will be fine.