Justin Timberlake vs. Barack Obama -- Who'd You Rather?

Justin Timberlake took to the White House last night to lead all the fancy schmancy peeps in a sing-along of Otis Redding's "Sitting on the Dock of the Bay"-- including President Barack Obama.

The JT & BO duet was for a PBS taping of "In Performance at the White House" honoring Memphis soul.

Two very powerful men ... but if you could only choose one, we gotta ask ...