I agree a system has to play everything, but you need a couple of high quality recordings you know well, to take to a demo. Mine are:
Lyle Lovett, Joshua Judges Ruth
Dvorak, Rusalka, , The Decca version, with Renee Flemming, the first few tracks.
If you think you don't like opera, just try that recording, it's just wonderful.
As an aside, the last time I saw Russalka, was at the Glyndeborne, in the UK. festival and the Soprano, in her excitement, flew 15ft off the stage into the orchestra. She was fine, the £30000 cello she landed on was terminal though. There was the inevitable call for a Doctor. Absolutely no point I thought, there'll be hundreds of them. Sure enough, I was persuaded to volunteer and was told they had 24 Doctors already!