I guess it depends on what you compare it to. If you compare a monster cable to the cheap things that come in the box when you but a $49 DVD player, then yeah quite a difference I would imagine. If you were do compare them to simply descent after-market cable then I think you may reach the point of diminishing returns.
Then again people are happy to spend untold fortunes on boxes of special volcanic soil to place their amplifiers on. They swear you can hear the difference
