Of the current crop of pop divas, Barbados-born Rihanna has proven to have one of the keenest ears for of-the-moment hits. Here are the best songs from Rihanna, her contemporaries, and the artists she's collaborated with.
Fitness experts agree that the perfect running cadence is 180 steps per minute. Run doubletime to this mix of hip hop songs -- all around 90 beats per minute -- and you'll keep a steady pace and reach your target heart rate without hitting the wall.