No. 7: Bon Iver

We acknowledge this one is a little out of left field, since Bon Iver’s indie folk-rock doesn’t have much in common with Bieber’s pop sound. But Kanye West saw fit to utilize frontman Justin Vernon’s unique voice on multiple tracks on ‘My Beautiful Dark Twisted Fantasy.’ If Bieber ever decides to record a sparse ballad – think a male version of Taylor Swift’s ‘Safe & Sound’ – Vernon would be the ideal choice to supply guest vocals, and the contrasting styles could make for something special.