What music do you use to assess your system?

In the end well recorded large scale classical works always set the highest bar in regards to what it takes to reproduce them best.

For me in addition to that, to cover all the bases safely, I always want to test with various forms of music that includes well recorded electronic music elements just to make sure things are up too the task of delivering the goods at higher volume with this stuff as well without any noticeable rounding, breakup, distortion, limited dynamics, etc.

If those two things can be done really well chances are you are in good shape for most anything else less challenging that comes down the pipe.

I just listen and enjoy without thinking too much about how it sounds, but how it makes me feel. I'm feeling mighty fine lately.

Bach Cantatas by Le petite band .
Kurt Elling/"Man in the Air"
The one and only Stanley Turrentine / "Joyride" on Blue Note. Great sound with fabulous band throwing in everything to include the kitchen sink !

Simply mic'd vocals with accompaniment (piano is good, but acoustic guitar will do), and recordings I've made myself with a pair of good condensers and a Revox A77.

Solo piano,flute,guitar,violin,cello, sax. String quartets,quintets. Mozart/Beethoven octets. Jazz w bass,drums and xylophone. Massive symphonic. All sipping warm brandy. Cheers.