You've just finished polishing your system and settling down to enjoy it. But how do you know it's right?
The short answer is: when it's real.
Imaging, tonal balance, toe in, toe out all matter to achieve only one thing: reality in your living room.
Does that singer sound like she is in the room with you? Does the orchestra sound like it's live, right there, right now when you close your eyes?
If yes then you know it's right. If no, then you need more work or different combinations of equipment.
And to those who get it right but then make it better, I'll answer the age old question: if it sounds real, how can it get better than real?
The answer is that "real" is an illusion and we are so far away from fooling people that musicians are actually in the room that "real" is relative and "right" is temporary.
But if you can relax and believe it's close to real, then it's right.