It is a reasonable question to ask if Barack Obama will outdo the Clintons in accumulating wealth in his post-presidency.  Gardiner Harris of the New York Times reports that the president has ambitions that would indicate wealth of that magnitude:

After he is out of the White House, President Obama has said that he wants to become a venture capitalist, own part of an N.B.A. franchise and avoid taking off his shoes during security screenings at commercial airports.

That last item, of course, indicates a desire to travel exclusively by private jet.  He will be off to a good start:

 All of those goals, serious or not, might soon be achievable if Mr. Obama and his wife, Michelle, sign post-presidency book contracts for what literary agents and major publishers say could amount to $20 million to $45 million — more than enough to pay the estimated $22,000 monthly rent for the nine-bedroom home they will occupy in the Kalorama neighborhood of Washington and foot the bill for flights on private jets. (Mr. Obama has said he would like to avoid commercial flights once he surrenders Air Force One.)

But as Richard Baehr pointed out to me, "he could be the first billionaire ex-president, given his age. At a hedge fund, he could do as little as Rahm Emanuel did at his firm, but earn 25 times as much."

One potential fly in the ointment: The National Enquirer has reported for months that the Obamas will divorce after they leave the White House.  I have no idea if their sources for this are equal to their enterprise reporting on John Edwards.

If the Obamas do divorce, that might halve the existing assets, but it would also mean that post-divorce earnings of Barack would not be claimed by Michelle, perhaps encouraging him to recover his financial losses rapidly.