Getting back to DC vs. Mariah. I would recommend checking out "God Rest Ye Merry Gentlemen" if you haven't already. I think Mariah does more with her own self there than DC has ever done in whatever lineup you care to choose.

And you were asking for DC examples. One that immediately pops into mind is "Say My Name" for me personally. Just listen to that intro and the difference between the first and second time they sing the chorus. And of course there's the 'regular' version of "No, No, No".