21. "Rude Boy" (2009)
There was a lot of pressure in late 2009 when Rihanna dropped Rated R, her followup to the juggernaut that was Good Girl Gone Bad. For a short time it seemed like the project might underwhelm when early singles "Russian Roulette," "Hard" and "Wait Your Turn" failed to become "Umbrella"-like mega-hits. But then in February of 2010, "Rude Boy" hit the airwaves. The dancehall song was the work of small army of songwriters, including Stargate, Ester Dean, Makeba Riddick, Rob Swire and Rihanna herself, and it quickly shot to Number One on the Hot 100 and stayed there for five straight weeks. No other song from the album was nearly as successful.