"Valerie" (Mark Ronson feat. Amy Winehouse)

In 2007, NYC-based British producer Mark Ronson released Version, a collection of R&B/soul covers of alt/indie rock and pop songs.  As you can imagine, covering the likes of The Smiths, Radiohead, and Britney Spears on the same disc with Motown-style arrangements produced mixed results.  
But a standout track on the album was a cover of The Zutons' 2006 indie rock song "Valerie," featuring the late Amy Winehouse on vocal.  In fact, it's one of those charmed instances where the artist covering the song owns it so completely that you almost don't associate it with the original.
The collaboration came about because Ronson had co-produced Winehouse's 2006 hit album, Back to Black, which itself had a 1960s throwback feel.  Ronson requested that Winehouse choose a modern rock song that she could cover for the Version project, and she suggested The Zutons' song--a track that Ronson initially wasn't sure was a good fit for her voice and style.  
Ultimately, "Valerie" would become one of her signature songs.
And the reason is crystal clear: Winehouse's interpretation and immaculate delivery retains the humor of the original, only it's tinged with her ever-present, Billie Holiday-like melancholy, which pushes the soul quotient to the max.
(Plus, there's the added bonus of lighthearted studio chatter at the beginning of the track, where Winehouse references a bit of Dave Chapelle.)