Hi,
In terms of Sonic Benefit, Aesthetics, and Budget:
For me, I have always needed to brake down this question a little further.
Things that cannot be changed easily (concealed cabling etc)
Sonic Benefit: 45%
Asthetics: 40%
Budget: 15%
At this point, IMHO, if you cannot afford to do it properly, why bother?
In terms of speakers.
Sonic Benefit:35%
Asthetics:35%
Budget:30%
Speakers should either look good or disappear but, need to sound really good but, are easily changed(with lots of hours of research). I try not to blow my budget as I would rather wait a year or 2 and save up for a replacement.
In terms of amps, preamps and components:
Sonic Benefit:70%
Asthetics:0%
Budget:30%
I tend to hide my amplifiers and components but, again I would rather save up for a better piece than to blow the budget too much.