How can you evaluate a system with highly processed music?

The performance and arrangement are certainly most important.

I do, however, most enjoy acoustic instruments and voices.

Heavily processed Pop, etc. can surely be a lot of fun. And the performance of my system can also be evaluated with any content. 
However, I believe acoustic instruments and vocals are able to be a gauge.

@quattro: I have a bunch of Peter’s recordings, made for Levinson, Audiofon, and Harmonia Mundi. Excellent sound and music.

You can’t evaluate your system’s abilities by playback of electronic and highly produced pop. I found that all my systems can recreate those genres effortlessly. My non-audiophile friends (sounds arrogant of me) always lose their minds when I play something “highly processed” as they experience that emotion that comes with hearing near perfect reproduction of music.. yes, I know that’s subjective….FWIW I’ve found that most of my listening sessions start with electronic music and that after 30 minutes or so I begin to get fatigued. It sounds fantastic initially but I think our brains aren’t suited to long listening sessions with that perfectly articulated sound. If you want to test your system (and acoustics) try a symphony or rock band. Yes, I know the list of variables is endless and subjective and open to fierce debate but these genres will reveal your systems weaknesses much faster than “highly processed” pop/electronic.

I knew I had the right system for me when I stopped listening to the equipment and concentrated on the music. I always use vocals, piano, violin, sax and cymbals to evaluate a system. Electronic music won’t show the accuracy or realism of a system IMO.

I don't know why you'd want to evaluate a system with music other than the kind that you like. Personally, I wouldn't care how music I don't listen to sounds on my system. I listen to rock and electronic, so how classical guitar sounds on my system would be meaningless to me.