A dark-horse possibility for 2012, Thune is a South Dakota senator who has focused on the country's fiscal situation. To get to the Senate, he defeated Democratic incumbent Tom Daschle, who had been the Senate majority leader.
As tangible evidence that he is gauging his prospects, Thune spoke to the conservative conference last week and is to address Lincoln Day dinners in Minnesota on Feb. 25 and Missouri on Feb. 26.
Barbour is the popular governor of Mississippi who helped the state rebound from Hurricane Katrina while neighboring Louisiana struggled. He was the party's chairman before moving to the Mississippi governor's house, and was also chairman of the Republican Governors Association.
A sound-bite machine with a Southern drawl, he is popular with reporters. He raised some eyebrows with a magazine interview recently in which he said he did not notice much about the civil rights movement while growing up in his Deep South state. He seemed to be trying to rectify the comments this week by proposing a civil rights museum for his state.
Distinguishing himself as a conservative who is "not angry," the former Arkansas governor used a mixture of anti-abortion, anti-gay politics and regular-guy charm to win the 2008 Iowa caucus against better-known candidates.
A Baptist minister with strong ties to conservative Christian groups, Huckabee continues to poll strongly in Iowa and has been considered a potential presidential front-runner in 2012. But he is also dogged by controversy from decisions granting clemency to convicted criminals in Arkansas, including a felon who later allegedly killed four Washington state policemen and died in a gun battle with a Seattle officer.
If there is one thing Palin has it's buzz. The former Alaska governor has used lucrative television, book and speaker deals to emerge as one of her party's biggest stars since being the 2008 Republican vice presidential nominee.
She is a leading voice in the fiscally conservative Tea Party movement and enhanced her influence by campaigning for its candidates across the country in last year's congressional elections.
But some Republican heavyweights are leery of Palin because she is a polarizing figure and her support seems to be limited to conservatives. In a self-inflicted wound, she caused controversy last month with comments about a media "blood libel" against her after Arizona shootings on Jan. 8.
Palin is still keeping her supporters guessing on whether she will in fact run.
Raised eyebrows in the White House by declaring his intention to resign at the end of April as Obama's U.S. ambassador to China and to let it be known that he is considering a race for the Republican presidential nomination.
Like Romney, Huntsman has roots in Utah and is Mormon. Huntsman is a former governor of Utah and is a moderate Republican, which may make it difficult for him to win over conservatives who play a giant role in the nominating process.
Huntsman's brother, Peter Huntsman, told Reuters on Thursday that Jon Huntsman will announce whether he is going to run for president in the next couple of weeks.
The New Jersey governor drew national attention as a corruption-busting U.S. attorney who won convictions or guilty pleas against scores of public officials. He has since proved a popular governor in a traditionally Democratic state, despite ardent stands against abortion and gay marriage.
In a visit to Washington this week, Christie railed against deficits and debts, criticized both parties and then declared he did not plan to run for president in 2012.
The celebrity real estate magnate has been talking up the possibility of running for president in 2012, which would give him the opportunity to use his signature line on Obama: "You're fired," from his NBC TV show "The Apprentice."
It isn't clear whether Trump is talking about running simply to add to his celebrity status, or whether he is serious. He was a last-minute entry into the list of speakers at the conservative conference.
(Reporting by Steve Holland; Editing by Eric Walsh)