cd's/SACDS to test highs?

I would use one of the early Nora Jones records. The vocals are very up front and on a good system, you can actually hear the sound of her mouth opening, and the breath sounds. On a poor system, you will either lose these things or the vocals will sound harsh, but on a good system, she sounds like she's in the room. BTW, the music was good on the first two records, as Nora wrote very few of the songs. She's a decent enough singer, but her writing is for shit.

I've never heard close-miked opera, so the highs are generally somewhat muted compared to more modern stuff. Of course, it's a more realistic portrayal of what one would hear from the audience, but I don't think that's what you're looking for at this point.