With soon-to-be Chicago mayoral candidate Rahm Emanuel set to leave Washington by week's end, speculation is heating up over who will replace him as White House Chief of Staff. (Watch an AP report about Rahm's decision.) Here's a look at five top contenders: 

Pete Rouse, senior Obama adviser
Rouse, Obama's chief of staff when he was in the Senate, "has emerged as the clear favorite" to step in, at least on an interim basis, say Glenn Thrush and Carol E. Lee in Politico. A longtime political insider, Rouse is known for a "low-key, media-allergic style" that "makes him a sort of anti-Rahm." Even though he's being discussed as a stand-in, Rouse "hasn’t been ruled out as Emanuel's long-term replacement if he thrives in the role and meshes with other staffers."

Tom Donilon, deputy national security adviser
In a crowded field of contenders, "the most likely candidate may be Tom Donilon," say Mike Allen and Josh Gerstein in Politico. "Democratic insiders" say Obama will pick someone "already in his orbit" but with an outside perspective. Not only does Donilon fit those criteria but his "political experience goes back to the Carter-Mondale campaign." Still, Donilon is reportedly hesitant to take the job, preferring to focus on foreign policy and national security.

Ed Rendell, Pennsylvania governor
Given the drubbing the Democrats face in November, Obama's "best political choice" may be the Keystone State's outgoing governor, says Ed Morrissey at Hot Air. Rendell is "much more pragmatic" and has a "better political ear" than anyone in Obama's inner circle. Plus, he's good with the media, "has plenty of political infighting experience, and is well-respected within the party."

Ron Klain, Vice President Biden's chief of staff
Biden's right-hand man "would be a natural fit for the job," says Laura Meckler in The Wall Street Journal. He has held top positions at the Clinton and Obama White Houses, on Capitol Hill, and at the Justice Department — plus he has private-sector experience. He might also be a good fit for Obama's 2012 election campaign, since he played a "pivotal role" in the 2000 presidential recount — Kevin Spacey portrayed him in an HBO movie about the Bush-Gore drama.

Leon Panetta, Director of the CIA
Although he is "not considered to be on Obama's shortlist" at the moment, says Politico, "some Democrats on Capitol Hill" favor the experienced Panetta, believing "he’d be best equipped to deal with a newly empowered" Republican party. He was a chief of staff during the Clinton administration but is still considered a White House outsider compared with other candidates. That status may help him in the long run, since Obama, who has "kept his plans close to the vest," may "opt for an outside-the-box pick should the political climate dictate it."

Update: Originally published Sept. 9, 2010. Revised on September 22 and Sept 29.