Most Important?

If you are talking digital then $1000 gets you a darn good source if you are
careful/selective (after you get diminishing returns). A darn good pre and
power amp can be had for around $5000 again being selective. $1500 is
where things begin in speakers but above $5000 is where things are
significantly improving although I would guesstimate that above $20,000 on
a speakers or $10,000 on a sub you are starting to reach into diminishing
returns. Room acoustics is very room dependent but an expense on par with
the cost of your source and amplification seems sensible. (Room acoustics
can easily do more damage to the sound than most entry level source/amps,
IMHO)

If you are looking at a TT you may have to spend a lot more on source - but I
have been out of that for a long time so I can't comment.

In my book you reach diminishing returns fastest with a source and amp and
slowest with speakers and room acoustics. Speaker and room acoustics is
where all the bad stuff happens (distortion, reverberation etc.) In that sense a
modest system in a good acoustic environment will outdo an all out assault
on equipment in an untreated poor acoustic environment.

Probably the single most important thing you can do is to get a house with a
a really good room for listening. No amount of effort will put lipstick on a
pig. As concert goers will know - some concert halls are stunning and
marvelous and others are just well impossibly bad.

Of course careful buying of used on Audiogon can get you all of the above
gear for a "song" if you are patient and don't mind old gear with a few dings
or scratches!!!

Wow - what an insane thread. Some of the polarizeed views suggest that Bose and Noel Lee has been extremely succesful at marketing their cheap speakers and expensive cables.

Anyone who thinks that any old speaker will do clearly does not understand the relative difference in distortion levels between electronics and speakers. I know the math can be daunting for some but fwiw we are talking factors of over a thousand times worse for good speakers and hundreds of thousands of times worse for an el cheapo Bose or its equivalent speaker.

Headphones anyone? (for $500 you can get a decent pair)

Has anyone even considered the room in this thread? About 50% of the sound we hear is indirect--coming from the speaker interaction with the room.

Yes I did mention that after speakers, the room acoustics was probably the most important thing. I agree with you 100%

As an example, is the 3% second harmonic distortion of a loudspeaker less consonant with the fabric of the music than .3% IM in an amp?

Good point but 3% distortion in a speaker is amazingly good and 0.3% IM distortion in an amp is lousy. You are quite right that some forms of distortion are far worse than others though and I agree that IM is one of the bad kinds - great point there. FWIW, there is a good correlation between IM distortion and THD figures for amps...low THD generally means low IMD. I agree speaker harmonic distortion is fairly benign - you scored another point there - although high 3rd harmonic is fairly common in speakers and this is BAD. Also speaker transient response is usually abysmal and looks nothing like a real transient (amps are usually very good at this) - so there are lots of details to argue over, however I maintain that speakers are usually the most inaccurate device in any audio chain.

.......the blue walls stay!

Oh dear! Oh dear! That is so sad ;-)

I have a blue house with a blue window
Blue is the color of all that I wear
Blue are the streets and all the trees are blue
I have a girlfriend and she is so blue
Blue are the people here that walk around
Blue like my corvette its sitting outside
Blue are the words I say and what I think
Blue are the feelings that live inside me