One recording that seems to have nearly everything is Das Reingold on Decca, conducted by Solti. If you have an original pressing, side 6 is nothing short of spectacular- nearly everything a stereo could be evaluated on: delicacy, bandwidth, impact, dynamic range, ability to hold together at volume, depth, soundstage width, detail, human voices, singularly and together, all ranges... its all there.
This recording puts most speaker/amp combinations right flat on their face nearly right away, if you are unwilling to change the volume as it plays. This is where the efficiency of the speaker, plus its ability to play high spls at the same time (BTW the two are quite different!) can play such a dramatic role.