Perfection

If there is a perfect vocalist, I think it's Sade. I've had a thing for her music for a long time. Not enough O's in Smooooooth to describe her voice. And she has a penchant for producing songs with the most amazing jazz-pop atmosphere.
Here's "Nothing Can Come Between Us" (lip synced to the studio version, but gives a good indication of the instrumentation for her live shows, which must be truly amazing...)