Relative component value to overall SQ.

Room optimization: 40%Speakers: 30Source, electronics: 30

As you no doubt realize opinions on this question will vary widely, in part because systems, components, rooms, listeners, preferred listening volumes, and listener preferences among different types of recordings (including the dynamic ranges of the kinds of recordings that are listened to, which can vary widely among different genres and labels and can dramatically affect power requirements and potentially the cost of both amplifiers and speakers), all vary widely.

But FWIW, my opinion is as follows:

Speakers 35%;
Room optimization 25%;
Amplifier 20%;
Preamp 15%;
Cables and Power Cords 5%, with that 5% being distributed differently among speaker cables, interconnect cables, and power cords depending on the specific components they are connecting.

Regards,
-- Al

Speakers: 50%
Amp/Pre or integrated: 25%
Room treatment: 5%
Speaker cable: 10%
ICs: 5%
Power cords 5%
Merry Christmas!

Conspicuously absent is what I consider number 1, the recording (source material).

All 100%, otherwise you are moving away from great sound. :)

I was going to say "slicing and dicing is a loser’s game," but that is too harsh. I simply have concluded from building hundreds of systems that all components of a system are critical. Diminish the importance of any 1 element and you are negatively effecting the system.

Obviously, one cannot allocate 100% of funds to 1 component. I have built systems with any given component or cables representing let’s say from 10% to 70% of the total rig cost and obtained wonderful results. Putting together a putative breakdown is only relatively helpful. Attempting to relegate particular components or cables to a secondary role is harmful to establishing superior sound.

Simply shifting around the percentages for each component gets you nowhere fast. When you are sitting at, let's say, a total of $3K for the rig, you can change it around all you want - you will still only have a $3K range of performance. You simply must elevate the cost structure of the system to holistically elevate the range of performance. You cannot know that unit you actually do it. And, when you have done it with hundreds of systems you know it is an absolute fact, not a myth. What's a myth is the idea that one can with a $3K rig typically reach performance of $10, 20, 40K rigs, etc. 

Blessed Christmas to all.