I’m curious as to why the consensus on this site, anecdotally speaking, seems to be that high powered amps are important enough to merit the extra cost? Unless you have a big room, or very inefficient speakers, most people shouldn’t need more than 60wpc. That is enough to drive your average speaker to unpleasantly loud volumes that are dangerous to your ears for sustained listening.
Most modern music has limited dynamic range, and simply does not generate large peaks in volume anyway, negating the need for high headroom amplification.
Most "pop" (considered very broadly) recordings are engineered to “sound loud” at low volumes, and the crazy amount of processing involved in this often introduces distortions which are unpleasant at loud volumes. It also results in a dynamically compressed signal which will stress your ears that much more at high levels. (Because you are subjecting yourself to more total sound energy on average).
If you really are a fan of orchestral music recorded with minimal dynamic compression, and you want to listen at near concert levels, then perhaps you need a lot of power, if your listening room is big enough to allow for a sizable distance to speakers (over 15 ft). This represents a vanishingly small audience. Most "classical" music recordings are compressed anyway, though not as much as a typical pop production.
A lot of people think "dynamic range" is a good thing in music, but in most cases it simply has to be controlled to make effective recordings for the "real world." Only the very best audio systems can come close to reproducing the full dynamic range of an orchestra.
There is a paradoxical aspect to dynamic range compression, which is that it usually makes things sound "louder" relative to anything else (like background noise). So compression can make things actually feel more "dynamic". There are a couple of aspects to this, but functionally it pulls quiet passages into a more audible range, and allows us to hear the dynamics of sections of music which might fall to low into the ambient noise.
The other factor which allows dynamically compressed recordings to deliver an experience that still feels dynamic, is that our ears are not that sensitive to dynamic level changes, but are very sensitive to timbre changes. Timbre communicates the bulk of the perceptual qualities of dynamic passages. Compression allows for more perception of timbre overall.
As an example of this overall issue, anyone that likes to watch TV with a decent playback system has probably noticed an annoying experience where within a program, or between programs, there are significant level changes.
Say a car chase scene comes on, with pounding music. If you had the level loud enough to where the dialog was clear, these passages of louder music, which are themselves heavily compressed (relatively speaking) will "wear your ears out" quickly, and you will find yourself reaching for the volume knob too much. Some AVRs are attempting to address this by building dynamic compression into the amp itself! (There are a lot of different types of compression.)
When it comes to useful standards, what I think we need are carefully constructed standards based on reproducible, double blinded, audibility testing. (Probably ABX is the most practical.) With a set of a standard tracks and speakers. New speakers and test tracks could be introduced over time, using the same testing methodology, and the results interpolated into the existing reference data. Testing for sound for video should be included as well.
Amps tested under this method could then be tested on the bench, and the results correlated with the listening tests. Listening testing is terribly hard and expensive, but my guess would be it would be well correlated with bench tests, allowing for practical testing of a wide range of products.
This is the basis of the speaker testing Floyd Toole and colleagues did. Without this careful listening tests, the results are not as useful. Once some baselines of audible performance have been established, it would free consumers to focus on more practical questions related to reliability, features, aesthetics, and of course, price.
