Annie Leibovitz/The 2009 Hollywood Portfolio. Some of these actor-director teams have a history together—remember Ron Howard and Tom Hanks’s breakthrough, Splash, a quarter-century ago?—while others produced their first mind-melds in 2008. Sam Mendes and Kate Winslet even brought marriage and kids to the Revolutionary Road set. But in each case the chemistry was profound, the effect exponential. From Gus Van Sant and Sean Penn to John Patrick Shanley and Meryl Streep, Annie Leibovitz photographs 10 partnerships that helped generate more than four dozen Oscar nominations this season.