A lot of interesting choices. When I check out a system, I generally try to play songs in a few categories:
1. Lots of chiming or shimmering guitars and I'm looking for whether that grates on me or sounds beautiful.
2. Songs with significant bass and I'm looking for fast, tight bass that doesn't distort or dominate the other sounds.
3. Songs with a lot going on to see if small details are heard clearly and whether the system mushes stuff together.