Let’s get the disclaimers out of the way: No one really knows if Timothy Geithner will leave the Treasury Department after the debt ceiling is raised or after the election concludes. Or maybe he’ll never leave. He’ll go all Phantom of the Opera on us and mane a new life for himself in the basement of the building. Future Treasury secretaries will swear they occasionally hear murmurs about leverage, punctuated by quick giggles, but their complaints will be chalked up to stress and exhaustion.

No matter how it plays out, he’ll eventually need to be replaced. Thus, the guessing game.

The Obama administration has a habit of promoting from within. Christina Romer was replaced by Austan Goolsbee. Peter Orszag was replaced by Jack Lew. Larry Summers was replaced by Gene Sperling. They also have a habit of turning to respected veterans of the Clinton administration. Which brings us to our first category:

Likely: Jack Lew, the current director of the Office of Management and Budget and a former Citigroup employee who enjoys unusually good relations with Republicans; Erskine Bowles, former chief of staff to Bill Clinton, co-chair of the fiscal commission, and Rep. Paul Ryan’s “favorite Democrat”; Gene Sperling, the current director of the National Economics Council and a former counselor to Timothy Geithner; Roger Altman, an investment banker who served as deputy Treasury Secretary under Clinton and almost got the NEC job earlier this year; Bill Daley, Obama’s current chief of staff and a former banker and Commerce Secretary; and Laura Tyson, a Berkeley economist who ran both Clinton’s Council of Economic Advisers and National Economics Council.

Choosing a Treasury Secretary is more difficult right now than it’s been in previous years as Wall Street is so tainted. But keep an eye on candidates from the tech world: the Obama administration would love to be associated with the vibrancy, ingenuity and forward-thinking of Silicon Valley. Which brings us to our next group.

Less likely: J.P. Morgan Chase chief Jamie Dimon may be the Obama White House’s favorite banker, and he’s certainly being pushed in some quarters, but the politics of naming a banker to this position are lethal; outgoing FDIC-chair Sheila Bair is a former Dole staffer and Bush appointee, but her relations with the White House economic team have been rocky, and she scares Wall Street; ex-Google CEO Eric Schmidt got floated to lead the Commerce Department, so he could perhaps make a comeback here; James Pethokoukis is hearing that Facebook COO Sheryl Sandberg, who was chief of staff to Larry Summers when he ran the Treasury Department, is being considered, but it’d take a special kind of person to prefer the Treasury Department in an age of austerity to Facebook during its age of expansion; GE CEO Jeffrey Immelt looks a lot worse after his company got dinged for aggressively lowering its tax burden.

What the White House doesn’t want, however, is an unwinnable confirmation fight, nor a candidate who will burn them later. Which brings us to the final group:

Not gonna happen: Elizabeth Warren would terrify Wall Street and couldn’t be confirmed; Paul Krugman and Joe Stiglitz got a lot of mentions in my Twitter feed, but I doubt either of them would want the job, and neither could be confirmed; Michael Bloomberg is an interesting choice, but he’s too ambitious, with too much of an independent power base, for the White House to trust him.