(Adds Edwards quotes, details)

By John Whitesides, Political Correspondent

DES MOINES, Iowa, Dec 27 (Reuters) - Democrat Hillary Clinton touted her experience and rival Barack Obama made his case for change on Thursday as White House hopefuls scoured Iowa for support one week before the U.S. state's too-close-to-call nominating contest.

Clinton and Obama were among 10 Democratic and Republican candidates who spent the day in Iowa, where next Thursday voters in both parties kick off the state-by-state battle to choose candidates for the Nov. 4, 2008, election to replace Republican President George W. Bush.

Polls show a tight Iowa race on both sides.

Clinton, Obama and John Edwards were in a three-way fight among Democrats and Mitt Romney and Mike Huckabee battled for the Republican lead in a state where a win provides vital momentum.

Obama, a first-term U.S. senator from Illinois who has been rapped by Clinton for having too little experience for the job, said he was the candidate who could end the partisan "food fight" and accomplish real change in Washington.

In a speech that took several swipes at Clinton, a New York senator and former first lady, Obama also poked fun at her husband Bill Clinton's statement that electing Obama would be a roll of the dice.

"The real gamble in this election is playing the same Washington game with the same Washington players and expecting a different result," he said in Des Moines. "You can't fall in line behind the conventional thinking on issues as profound as war and offer yourself as the leader who is best prepared to chart a new and better course for America."

Obama, an early opponent of the Iraq war, has criticized Clinton for voting in the U.S. Senate to authorize it. He and Edwards, a former North Carolina senator, also have attacked her vote to label an Iranian military group a terrorist organization as potentially paving the way to war with Iran.

Clinton stressed her experience as she joined other presidential candidates in decrying the assassination of Pakistani opposition leader Benazir Bhutto.

"I have known Benazir Bhutto for a dozen years and I knew her as a leader, I knew her as someone who was willing to take risks to pursue democracy on behalf of the people of Pakistan," she said in Lawton, in northwest Iowa.

'WHO DO WE LEAVE OUT?'

She also took a shot at Obama's health care plan, which critics say would leave up to 15 million Americans uninsured.

"Who do we leave out -- do we leave out this woman who's a nurse but doesn't have health insurance?" Clinton asked, pointing to a woman in the audience.

At a campaign stop in Decorah, Iowa, Edwards also mentioned his past meetings with Bhutto and said he spoke to Pakistan President Pervez Musharraf after the attack and urged him to continue the democratization process in his country.

Several top Republicans were notable exceptions to the focus on Iowa on Thursday.

Huckabee, the Baptist minister and former Arkansas governor who has been surging in polls, was in Florida most of the day.

Romney, the former Massachusetts governor, chatted with diners at coffee shops in New Hampshire, which holds its nominating contest on Jan. 8, five days after Iowa.

"I think this will be a challenging race. New Hampshire makes it interesting," he said at Norton's Classic Cafe in Nashua, where he nibbled on a Greek pastry.

Romney, who along with Huckabee has been criticized for a lack of foreign policy credentials, has seen his lead in New Hampshire evaporating under the advance of rival Arizona Sen. John McCain, a former Vietnam prisoner of war.

Former New York Mayor Rudy Giuliani was in Florida, which holds its contest on Jan. 29.

He returned to a familiar theme, his leadership after the Sept. 11 attacks in New York, in unveiling a new television advertisement to run in New Hampshire and Florida, and on national cable television, featuring images of firefighters at the World Trade Center ruins.

"When you try and come here and kill our people, we're one and we're going to stand up to you and we're going to prevail," Giuliani says in the ad.

Giuliani, who has seen his lead in national polls shrink and in some cases disappear under the surge from Huckabee, has concentrated on later voting states like Florida and the 22 states holding contests on "Super Tuesday" on Feb. 5. (Additional reporting by Scott Malone, Caren Bohan, Ed Stoddard, Andy Sullivan, Carey Gillam; Editing by Doina Chiacu) (For more about the U.S. political campaign, visit Reuters "Tales from the Trail: 2008" online at http://blogs.reuters.com/trail08/)

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