Futures markets on 20 world events: Are these prices too high or too low?

[Mr. Morden]

I've taken the betting odds on 20 future events from 5 different online betting sites (Intrade, Paddy Power, Betfair, Ladbrokes, and Sportsbet), and converted their odds into probability format.  Are the probabilities listed on each of these 20 things happening too high or too low?  (Of course, you don't have to give opinions on all 20.)

Intrade:
Assad to no longer be Syrian president by Dec. 31, 2012: 53.9%
USA and/or Israel to launch air strike against Iran before Dec. 31, 2012: 25.9%
Republicans to win control of US Senate in 2012 elections: 51.8%
Any country currently using Euro to announce intention to drop it by Dec. 31, 2013: 50.0%
Any country currently using Euro to announce intention to drop it by Dec. 31, 2014: 62.5%

Paddy Power:
Euro to no longer exist as an official currency in 2016: 20%
Next Pope to come from South or Central America: 27%

Betfair:
Labour to win most seats at next UK general election: 54.1%
Yvette Cooper to be the next Labour leader: 32.9%
David Milliband to be the next Labour leader: 18.9%
George Osborne to be the next Conservative leader: 13.0%

Ladbrokes:
Ed Milliband to be Labour leader at next UK general election: 75%
Andrew Cuomo to be 2016 Democratic nominee for president: 7.7%
Joe Biden to be 2016 Democratic nominee for president: 9.1%
Hillary Clinton to be 2016 Democratic nominee for president: 25.0%
Hillary Clinton to be elected US president in 2016: 14.3%
Jeb Bush to be elected US president in 2016: 4.8%
Marco Rubio to be elected US president in 2016: 4.8%

Sportsbet:
Julia Gillard to lead Labor at next Australian general election: 32%
Kevin Rudd to lead Labor at next Australian general election: 32%

[Stranger in a strange land]

Intrade:
Assad to no longer be Syrian president by Dec. 31, 2012: 53.9% - too high, though I doubt he'll still be in power 2 or 3 years from now
USA and/or Israel to launch air strike against Iran before Dec. 31, 2012: 25.9% - too high
Republicans to win control of US Senate in 2012 elections: 51.8% - about right
Any country currently using Euro to announce intention to drop it by Dec. 31, 2013: 50.0% - about right
Any country currently using Euro to announce intention to drop it by Dec. 31, 2014: 62.5% - about right

Paddy Power:
Euro to no longer exist as an official currency in 2016: 20% - too high
Next Pope to come from South or Central America: 27% - about right

Betfair: don't know enough to intelligently comment

Ladbrokes:
Ed Milliband to be Labour leader at next UK general election: 75% - don't know
Andrew Cuomo to be 2016 Democratic nominee for president: 7.7% - too low
Joe Biden to be 2016 Democratic nominee for president: 9.1% - about right
Hillary Clinton to be 2016 Democratic nominee for president: 25.0% - no way to say: if she runs it's basically hers, but there's no telling if she will or not
Hillary Clinton to be elected US president in 2016: 14.3% - see previous
Jeb Bush to be elected US president in 2016: 4.8% - too high
Marco Rubio to be elected US president in 2016: 4.8% - about right

Sportsbet: don't know enough to intelligently comment