We strive to handle important issues first to make way for follow up problems later. Like choosing the right blend of equipment vs. connecting it together. The first trumps the second, though both are important.
Figuring out where to best place your energies can often be challenging. For example, the best speakers in the world won't sound good without proper setup. Imagine placing a pair of Magneplanars hard up against the front wall. The sound would be dreadful.
One rule of thumb I have come to live by is to separate our importance focus into two categories: electronics and speakers.
In choosing electronics we should narrow our focus to synergy. It is far more important to have a synergistic group of products than a hodgepodge of excellent kit that does not play well together.
Loudspeaker choices have more to do with setup and room than the actual model. The weakest and strongest speaker models can suffer or benefit from setup.
These two extremes have to be taken with grains of salt. If you're too literal with this advice you'll wind up with a well setup boom box driven by pleasing electronic crap.
But, taken in the common sense spirit this advice was intended, it's a good rule of thumb for future system building.