[Early B.]

I hope Danny doesn't mind, but I couldn't find a circle that this topic neatly fits into. Hopefully, it will be interesting and informative for everyone.

What do you consider to be the 5 most important and essential elements for achieving great 2-channel sound?  I'll start...

1. power management (i.e., power conditioning, power cables, etc.)
2. open baffle speakers
3. stereo subwoofers
4. sufficient room size for optimal speaker placement
5. a pregnant bank account

When I thought about this, I was surprised to find that none of my top 5 included a specific component (amp, pre, DAC, transport, etc.).

[RDavidson]

To me, amp and speaker combo should be thought of as a sub-system, within the larger whole system.

[Folsom]

I think that's pretty good. I wouldn't put open baffle necessarily myself, which means stereo subwoofers may or may not be as big a deal (but I love them). But power conditioning is definitely number one. It's the factor for how much I listen baring no damaged equipment; and can make gear that's not fantastic worth listening to.

But I might put a stepped attenuator or digital volume... Pots are like ear muffs to me.

[SoCalWJS]

1)Acoustical considerations
  a)Size of room (in relation to speakers)
  b) ratio (HWD - "golden ratio")
   c) Treatments
  d) Speaker placement
   e) listening position and chair
1a) Speakers (personal preferences are a major consideration)
3) Source/pre/Amp
4) Power conditioning
5) Cables

[MarvinTheMartian]

I: Music choice - You have to enjoy the genera 
II: Source quality - cleaned vinyl - CD absolute minimum !!! 
III: Source delivery - platter > MC cartridge > phono pre - burn > ssd > interface > DAC
IV: Line level - volume + buffer
V: Headphones -  with only have 5 essentials I'll have to stop here ( next VI: Man cave acoustics ++)

The biggest change to my listening pleasure was a friendly digital interface = more variety.
Shawn
 

[bdp24]

Marvin and SoCal already pretty much nailed it, but here goes:

No.1: Has to be the recording, obviously.
No.2: The speaker/room combination; they can't be considered separately. This includes the speakers/subs themselves, the dimensions and proportions of the room (what I wouldn't give for a 10' X 16' X 26' room!), and acoustic treatment of the room.
No.3: The device playing the recording---the turntable/tone arm/cartridge/phono amp, the CD/SACD player, the recorder (I have recordings I made myself using a pair of omni condenser mics into a Revox A77. THE way with which to ascertain the accuracy of a loudspeaker! That's how J.Gordon Holt did it.), etc.

[Wind Chaser]

1)Acoustical considerations...
  d) Speaker placement
   e) listening position and chair

Many say the room is important; but it is amazing to me how little, if any thought many put into the the set up.

[Early B.]

Many say the room is important; but it is amazing to me how little, if any thought many put into the the set up.

Many people have severe limitations with their room for a variety of reasons. I cringe whenever I see audiophiles spend $10K on floor standers and put them directly up against the back wall because they don't have enough space, then rave about how good they sound. Seems like a waste of money.

[Hank]

1)  Room treatment
2)  Speaker quality - name your poison:  open baffle, electrostatic, etc
3)  Amp quality
4)  Preamp quality
5)  Recording quality

You can interchange numbers 2 through 5, but I leave 1) at the top. 

[Tyson]

1.  Open baffle speakers (particularly bass). 
2.  Room size/shape
3.  Room Treatments
4.  Tubes!  Electronics quality (Amp, DAC, Preamp, etc..)
5.  Dedicated electrical lines and/or power treatment

[sts9fan]

1) Quality sealed speakers
2) SMPS
3) Best fuses you can buy
4) Digital Cables
5) amp (SS only!)

[corndog71]

1. The best speakers you can afford  (Not necessarily the most expensive)
2. A great amp
3. Room treatment
4. A great preamp
5. Great music!

[musicalal]

1. A well balanced setup

2. A well designed room

3. Good quality cables

4. Exceptional quality recordings

5. An understanding wife/girlfriend

[geowak]

1. Healthy ears- how long has it been since you had a hearing test?
2. Speakers and room
3. Best source you can afford
4. Decent clean power
5. Good recordings
Preamp is not needed. But sometimes it can really help if it's very good.

[brother love]

1. dedicated room that allows for proper speaker placement & listening position(s) with sound treatments   
2. quality speakers   
3. properly sized amp with good synergy for selected speaker sensitivity & desired SPL listening preferences   
4. tube preamp   
5. quality primary input device: DAC, CD, turntable   

[S Clark]

1. Healthy ears- how long has it been since you had a hearing test?

It is a misconception that only those with good hearing can tell the difference in a high quality system and an exceptional system.  If the limitation is the common high frequency loss, you can still listen for accurate placement, voicing, soundstage and depth, and note decay.  When the top of my hearing range was around 7K, I would often evaluate diy speakers along side some highly respected industry pros, and always found my notes to be consistently in line with other evaluation rubriks.  As my hearing has continued to diminish, I find it harder to pick up soundstage cues, but imaging and decay are still easy to distinguish. 
Hell, I can still hear the difference in power cords.   

[S Clark]

1. A well balanced setup

2. A well designed room

3. Good quality cables

4. Exceptional quality recordings

5. An understanding wife/girlfriend

This a list that I can agree with, just put 5 and 4 at one and two.