Obama and McCain await voters' decision

* At least 130 million Americans expected to vote

* Obama leads McCain in every national poll

* World stocks rise before outcome

By John Whitesides, Political Correspondent

WASHINGTON (Reuters) - Democrat Barack Obama and Republican John McCain faced the verdict of Americans voting on Tuesday after a long and bitter struggle for the White House, with Obama holding a decisive edge in national opinion polls.

A record 130 million U.S. citizens or more were expected to vote on a successor to unpopular Republican President George W. Bush. The winner will set the U.S. course for the next four years to tackle the economic crisis, wars in Iraq and Afghanistan, a health-care overhaul and other issues.

Long lines of people waited to vote at some polls in battleground states, including Pennsylvania, Ohio and Virginia. Polls close in parts of Indiana and Kentucky at 6 p.m. EST/2300 GMT and over the following six hours in the other 48 states and the District of Columbia.

Obama, 47, a first-term senator from Illinois, would be the first black U.S. president. Opinion polls indicate he is running ahead of McCain in enough states to give him more than the 270 electoral votes he needs to win.

A victory for McCain, 72, would make him the oldest president to begin a first term in the White House and make his running mate Sarah Palin the first female U.S. vice president.

McCain's hopes for an upset rest on a tightening trend seen in some polls last week, or the possibility that all the polls have overestimated Obama's support.

World stocks rose to a two-week high and U.S. stocks gained with major indices up more than 2 percent, as investors looked with relief to the end of the campaign.

Analysts have said market prices probably already reflected expectations of an Obama victory. But if Democrats tighten their control of Congress, it may be easier for the new administration to deal with the financial crisis.

Opinion polls showed Obama ahead or even with McCain in at least eight states won by Bush in 2004, including the big prizes of Ohio and Florida. Obama led comfortably in all of the states won by Democrat John Kerry in 2004.

In Ohio, Ian Edwards said he voted for Obama.

"Very simple," the chief executive of a small technology company said. "Bad war. Bad economy. Bad reputation overseas."

Jerry Fritsch, in Scottsdale, Arizona, said he has nephews serving in the U.S. Marine Corps and he picked McCain for his military policies. "I don't want anybody who is going to screw with the Marine Corps heading up our main office," he said.