Top two most important sound qualities

I just think you need to like it.   There's so much confirmation bias, escalation of commitment, and subjectivity that it's scarcely possible to say what's really going on here. The continual upgrading turned me off eventually. 

The system should be suited to the space, it should be something I can live with.  It should play the kind of music I listen to most well. I don't want a system that dominates the room from an interior design perspective. 

Ultimately, I feel that the key component is to acknowledge the diminishing rate of return and to isolate oneself from the ongoing dissatisfaction that reading web forums brings.  I glance at the digest for this one and comment once a month at most. 

We've got a couple of Omega systems running off small tube amps with discreet subs and I think I am done with audio purchases forever. They sound great with the kind of indy folk stuff we listen to.  Mids matter most because that's where most of the information is anyways. 

Fright and goosebumps 

1. Extremely low noise

2. Accurate tonal balance

@bdp24 

Most loudspeakers sound comically "small" to me, the image of a grand piano, for example, being reduced to a miniature of it’s actual size.

Good point. I guess we don't expect lifesize image from HiFi because 99% of the systems we have ever heard don't have it. 

I graduated from bookshelf speakers to floorstanders and then 15  inch dual concentrics and whilst each one got better in this regard none of them have life sized imagery.

@panzrwagn 

Effortlessness - that sense of ease that allows you to forget about the hardware and just hear the music.

That's another easy one to forget.

Real music doesn't sound forced or strained but many systems do.

You probably need the right combination of loudspeaker and amplifier to get that sense of ease.

Usually that means bigger and more powerful.

Tonality, clarity, sound staging/imaging. In that order.