The election of Barack Obama as President
Almost everyone thought it would happen one day. That the United States of America would elect a man of color as President. But prior to Barack Obama's annouced candidacy in 2007, almost no one thought it would happen so soon. Throughout that year it was still a long shot. In 2008, even though he was the frontrunner virtually all year long, election day in November was clearly the most significant day in the year. That a person who represented the descended of former slaves (though not actually) rose to become the leader of the free world is clearly a watershed moment. Senator Obama showed through his organizational skills, deft strategy, and utilization of the benefits he had both personally and politically, outshined and smothered Hillary Clinton's bid to be the first female President. John McCain only had a small chance to win, and even in that it wasn't a substanitive one.
Regardless of what happens going forward good or bad, this was an incredible reflection of the American people.
Nothing else in the decade compares.