What Volume do you listen at?

I listen at 70dB and 80 only rarely. Probably because I haven't damaged my hearing from listening at high SPL's. However some people's ears can take the abuse. Sure live music is loud but that does not mean just because it is acoustic you ears are designed to handle that kind of volume level. Studies have shown that even extended listening at 80dB causes hearing damage, YMMV.
A good speaker should come to life at 70dB or lower and usually one that cannot won't resolve the fine details which account for small dB changes. There are always exceptions to this, of course.
I would suggest getting a speaker which is optimized for the SPL's you listen at.

With classical music the correct volume is when you can hear the softest passages. I have left my volume control here and never change it no matter what music I play. So with some music like Jazz, Rock, Pop it does sound louder than usual but according to my RS SPL meter, never louder than 85 dB.
I have noticed that some visitors do listen at much louder levels and I have accomodated them by turning the volume up to something like 95dB which is more than twice as loud as my normal listening volume.
The simple answer is what you (don't forget the rest of the household and your neighbours) are comfortable with.
See this link http://www.dontlosethemusic.com/home/areyouatrisk/protectingyourself/ if your SPL meter shows anything above 85dBs.

I find that as systems get better, one tends to listen at a LOWER volume, not higher. To some extent, higher average volume is used to compensate for a lack of dynamics and "boogie" factor.

I know there are all sorts of measurements that show that one must achieve 110+ db to realistically capture the dynamic peaks of real instruments. But, the fact remains that no commercial recordings offer realistic dynamic range and most listeners would find such recordings undesirable (too soft in quiet passages for the car, etc.).

I generally find that most listeners of classical music listen at a MUCH higher average listening level than one hears at a concert. This is, in part, to compensate for the lack of real impact and scale from recordings vs. the live experience. The better a system is at reproducing dynamic impact and scale, the lower the average listening level required. If one sets the peak level of a recording at say 100 db, the average level would be unnaturally, and for me unbearably, loud.

As for popular music, I like the fact that I can listen to music at much lower levels than a concert. I think listening at home and listening at a concert are completely different experiences. Frankly, if my system sounded as bad as a live concert, I would junk it in a flash.

> Grand Piano = 110 db SPL, Drum Set = 115 db SPL...

These figures get thrown around a lot, but need to have a dose of moderation applied.

Those figures are correct if you are standing next to the instrument while someone is banging away as loud as they can.

In reality, sound level decreases by the inverse square of distance. (I acknowledge this is a free-field figure and is affected by reflection and absorption.) However, if you are sitting with 2,800 other people in a 30,000 or 40,000 square foot concert hall listening to an unamplified grand piano on the stage, you are not going to hear 110 dB from the instrument.

There are certainly some audiophiles whose goal is to get 100-plus dB average volume levels from their systems. However, in a typical home listening room of perhaps 200 to 400 square feet, many (if not most) people are not interested in bringing the up-close volume of a full symphony into their living room. What they really want is an appropriately scaled representation.

For someone like me, tonal accuracy, low distortion, good imaging and a sense of space are more important than bringing venue volumes into my home.

At best, even the finest, most expensive stereo is just providing clues that suggest reality; they never duplicate it. Each of us varies when it comes to prioritizing the many different clues in order of preference. For me, sheer volume ceased to be near the top of the list a long time ago.

However, ask a hundred audiophiles, and you'll likely get a hundred answers.

One thing I have learned is to wear ear protection for everything but listening to music. Such as lawn mowing, chainsawing, snow blowing etc. This saves the ears for music listening.