This R&B icon has navigated dozens of stylistic trends over the years while always managing to make her clear, nimble voice the star of any arrangement. As part of the '70s outfit Rufus, Chaka Khan's voice sailed over the relaxed funk of “Tell Me Something Good,” written by Stevie Wonder. A decade later, she put melismatic touches on the New Wave–inflected groove of Prince's “I Feel for You,” making it a hit for herself. At other junctures, she's enlivened disco-indebted rave-ups (“I'm Every Woman”) and dueted with descendants like Mary J. Blige.