From Obama to McWho? Where punters are putting their money in the lead up to the 2012 U.S. Presidential Election

It only takes a casual glance at the U.S. media to know that, aside from the incumbent president, guesses as to who else will contest next year's race for the White House are somewhat unrealistic and all over the place.
Here's where the average punter is laying win-only money (market depth) at Betfair according to OddsChecker:

2012 Presidential Election - Next President
Barack Obama	1.89 $36	1.9 $1359	1.91 $106
Mitt Romney	4.3 $223	4.4 $19	4.5 $4
Newt Gingrich	5.6 $30	5.7 $79	5.8 $3
Ron Paul	28 $4	30 $95	32 $18
Rick Perry	60 $3	65 $9	95 $5
Herman Cain	60 $12	100 $27	130 $18
Hillary Clinton	34 $5	40 $5	60 $9
Jon Huntsman	3.75 $15	24 $6	38 $13
Michele Bachmann	25 $3	38 $12	50 $20
Rick Santorum	250 $3	300 $4	320 $6
Gary Johnson	380 $3	390 $4	400 $3
Rudolph Giuliani	100 $66	200 $7	1000 $32
Joseph Biden	380 $3	490 $3	500 $5
Sarah Palin	400 $10	410 $4	500 $5
Michael Bloomberg	420 $3	520 $10	550 $11
Donald Trump	300 $6	360 $7	430 $3
Chris Christie	840 $3	990 $3	1000 $14
Mitch Daniels	590 $3	650 $3	770 $3
Tim Pawlenty	250 $3	500 $3	1000 $58
David Petraeus	130 $3	250 $3	1000 $41
Mike Huckabee	920 $3	980 $3	1000 $18
Jeb Bush	27 $13	500 $3	1000 $22
John Thune	60 $7	500 $3	1000 $44
Haley Barbour	30 $3	34 $7	1000 $96
Marco Rubio	25 $3	500 $3	1000 $45
Bobby Jindal	90 $15	500 $3	1000 $82
Condoleezza Rice	500 $3	730 $3	1000 $56
Lindsey Graham	130 $3	500 $3	1000 $80
Mark Sanford	3.5 $3	500 $3	1000 $92
Charlie Crist	60 $7	500 $3	1000 $86
Chuck Baldwin	500 $3	640 $4	1000 $84
John McCain	500 $3	610 $8	1000 $94
Bill Owens	30 $12	500 $3	1000 $89
Fred Thompson	60 $14	500 $3	1000 $92
Evan Bayh	40 $15	500 $3	1000 $93
Tom Ridge	75 $9	500 $3	1000 $78
Al Gore	90 $7	410 $3	520 $3
George Allen	300 $4	500 $3	1000 $93
George Pataki	34 $9	500 $3	1000 $90
Bill Frist	3.5 $3	500 $3	1000 $88
Janet Napolitano	3.5 $3	500 $3	1000 $92
Sam Brownback	480 $3	500 $3	1000 $90
Eric Cantor	40 $7	500 $3	1000 $82
Jim DeMint	44 $7	50 $7	1000 $66
Mike Pence	3.5 $3	500 $3	1000 $82
Kay Bailey Hutchison	100 $10	500 $3	1000 $88
Rob Portman	90 $6	500 $3	1000 $86
Dirk Kempthorne	100 $11	500 $3	1000 $88
Scott Brown	3.5 $3	500 $3	1000 $76
Paul Ryan	470 $13	500 $3	1000 $52
Mark Warner	90 $6	500 $3	1000 $84
Tim Kaine	100 $10	500 $3	1000 $87
Rand Paul	3.5 $3	75 $7	1000 $55
Fred Karger	90 $6	500 $3	1000 $88
Alan Grayson	120 $7	500 $3	1000 $85
Alvin Greene	120 $7	500 $3	1000 $85
John Boehner	70 $7	500 $3	1000 $85
Chuck Hagel	120 $7	500 $3	1000 $85
Duncan Hunter	120 $7	500 $3	1000 $85
Norm Coleman	120 $7	500 $3	1000 $85
Jim Webb	120 $7	500 $3	1000 $85
Kathleen Sebelius	120 $7	500 $3	1000 $85
Caroline Kennedy	120 $7	500 $3	1000 $85
Thaddeus McCotter	3.5 $3	500 $3	1000