A stupid question for which there's no sensible answer.

1) Speakers.
2) See #1
2a) Measurement microphone and learn to use REW.
3) Speaker positioning
4a) Room including treatment (once you established how you want 3)
4b) Bass -- using room treatment, bass array?
4c) Chair -- its part of room treatment and speakers (height)
5) Source - what’s your flavor? -- need to find your flavor. Groups turntable setup and digital setup together.
6) Amplifier
7) Preamp (assuming 6 is good -- they are a set)
8) A dedicated AC line, possibly with a sub-box.9) Adequate cables.


If you get 1-7 right, you won’t be spending all your time tweaking cables and convincing yourself you made a difference while still living with all the other problems. If you have really dirty power, a conditioner may be in order.

Since I am not contentious enough, I would go on a limb and say I would take a great pair of speakers in a properly implemented room with a high end Anthem or Denon receiver and Spotify over much of what I see on here. I listen to music, I don't listen to my system.

Who gives a rat’s behind? 
 Enjoy the music.

Most people have never listen to their system 

How true, but how many times i said "that's it" and how many more i found the next sonic upgrade step within the same system. New, old, oldest, humble, expensive, it does not matter.
Know your system, your budget, and make the changes that suit your preference, from fine tuning adjustments to even adding a new component.
Any change though should not be focused on one thing and others ignored.

G

@hilde45, I have heard $200,000 systems sound bad in great rooms.
It is a game of leapfrog. We Identify the weakest link in the system and improve on it. Sometimes there is a specific problem we want to solve. I always wanted a little better high frequency dispersion than what I was getting from Acoustat 2+2s. Everywhere in the room except dead ahead of the speaker had high end roll off. In the listening position they sound awesome. Could not ask for better. The solution was getting a pair of Sound Labs (still awaiting shipment) By design they will disperse better for sure and they should sound as good. The operative word there is should. I have an Alpha USB to get music off a computer. It only has one output (at a time). I need to send signal in two directions so I purchased the M2Tech trio. They are supposed to arrive today. By one account it is a step down. We shall see. I think it has a better clock. But hey, how many of you own Italian Hi Fi gear? Should be an experience. 
The weakest link varies from system to system. It would usually be best to go after it first since most of us can only do one thing at a time. At some point moving up becomes prohibitive or silly. Nobody has to spend more than $150,000 on a system. IMHO spending more is either a matter of ego or lack of knowledge. I had very wealthy clients that gave me carte blanche. Boy was that fun. It was not just getting them equipment by the way. I installed it all in custom cabinets working with the cabinet makers. Back then you only wanted to see the face plates, nothing else. This was down in Miami. Many of the houses built by the water were up on pylons. There was usually a 3 foot crawl space under the house. I would drill holes in the floor under the cabinets and by the speakers running wire under the house then calk the holes. I would frequently come out from under the house looking like a tar baby. Some people wanted speakers all over the place including around the pool.  
My favorite installation was in an antique armoire. I had to do it without so much as a scratch.
Sorry for getting off topic! Run on thinking. Maybe I'm getting manic again.