Mine is Bruckners Symphony No 4, directed by Sergiu Celibidache with the Munich Philharmonic Orchestra.
It shows, if your system has stage, you hear many (unwanted) details, like coughs in the audience, creaks of the wooden stage, turning of pages.
Of course, in general nobody wants coughs. These are unavoidable in classical live recordings though. In this case they give a tremendous impression of the width and depth of the listener side of the Gasteig music hall in Munich.
With a low- or mid-fi system, you wont her the coughs at all. The same is true for the sounds of the instruments mechanics or the breathing of the players.
In the beginning, these sounds were annoying me a lot. But, as I bought more stuff, I found out that on high end electronic these are the easiest benchmark because they are barely audible.
The same with people who speak in the audiences: Who live at Hull for example, or Stones Get Yer Ya-Ya's Out ("Paint it black, you devil"
). If you understand it all, the equipment is not too bad.
The Bruckner recording also contains silent passages (second movement) with contrabasses playing the deep notes. This is a good probe how deep your system really goes. You will also hear, if your system can reproduce the colorful and complex overtones of old wooden instruments.
Not to speak of the incredible dynamics of the recording of more than 21 db. There are crescendi, where you may test how good your system can handle complex passages etc. etc.
Bruckner contains no piano, though, which is always good to hear too. I like to combine the Bruckner recording with Rapsody in Blue - Bernstein on the piano and conducting, New York Philharmonic from 1959. The Piano sounds more detailed on the LP recording, especially concerning the hammers hitting the strings, but for the real Piano sound, the CD is a good source too. Finally voices, either Dylan ( the new Blood on the tracks SACD) or Maria Callas (Naxos' Norma in Mono).
Maria Callas has also sort of complex overtones in her voice
.