I think I have the perfect CD for this. My father-in-law recently sent us a CD by a Portland-based band named Pink Martini. The CD is titled Hang on Little Tomato. It is an excellently performed album, and is excellently mastered, as well --- with the exception of a couple vocal tracks which contain minor but noticeable (at least on my M22s) sibilance.

I think it would be a perfect demo disc for this purpose. Plus, if you're looking for new music that is quite infectious, this one fits the bill.