It is interesting how lop-sided some of the posts are. it is true that each part of a system has its own 'weight' in the final outcome, but none are the end game either.
In one post though it was the truth as to what your mood might be for music one day and not as much the next. That might mean that where a certain cable or speaker set up decision leans towards one side of the musical spectrum more than another. I come across this in my system too, and most often the difference may depend on whether I listen to vinyl or CD. For me, they are not the same so there is one way to determine what source I will choose. Aside from that, using acoustic panels are another thing that I decide to use or not. This has way more to do with the trouble of putting the panels in place and then taking them down before the wife gets home.