SI's Greatest Shots of '08

"For pictures to be effective they have to be affective," says SI photography editor James Colton. "They have to invoke a reaction -- make you laugh, make you cry, make you cringe, make you linger just a little big longer to absorb all they have to offer." Here, then, are SI's best shots of 2008, beginning with Michael Phelps' split-second victory at the Beijing Olympics.