I fully agree with using somewhat poorly recorded music with known distortions to evaluate equipment. You can easily tell when a component adds in additional distortion or cleanly presents the trouble spots. 'Perfect' recordings can be the hardest to evaluate with since added distortions (harmonics) can often sound very pleasing added in. I had a friend who couldn't leave a room at an audio show that was using a massive OTL amp when using his favorite trumpet recording. It sounded lovely, but I found other instruments in his tracks were hard to define. Massive harmonics were being added. I played his recording at home and it sounded so much more 'real' and let him hear the difference at his next visit. But, some of my fondest listening memories are with equipment that added in some really pleasing harmonics, so it all works as long as we don't proclaim an intolerant opinion. =:>)
'The Old Grey Whistle Test' is a good start to decide what 'music' to test your likes and HiFi too. If it's got a decent tune or melody of which you can remember and repeat at least a few notes in your mind or head, your halfway there already. Does its reproduction from your hardware match or exceed your expectations ? Whatever it may or may not have cost. Cheap and cheerful or expensive and 'state of the art', it doesn't matter really , does it ?