Madonna - "Jump"

Arguably Madonna's best dance song since 1990's "Vogue" was "Jump" from her Confessions on a Dancefloor album in 2006.  The song didn't get played by many CHR/Top-40 radio stations, but did climb to #21 on the Hot Adult Contemporary Chart.  Had Madonna waited a couple years for the Timbaland/David Guetta/Calvin Harris era to begin, the song would have been her defining song of the 2000s.