One thing to consider about all those opinion polls floating around are what the pollsters are asking.
For instance, Harris-Decima asks "If a federal election were being held tomorrow, who do you think you would be voting for in your area…the Liberal Party candidate, the Conservative Party
candidate, the NDP Party candidate or the Green Party candidate?"
But I bet you would get a different result if the same pollster asked the question this way: "If a federal election were being held tomorrow, who do you think you would be voting for in your area ... the Stephane Dion Liberals, the Stephen Harper Conservatives, the Jack Layton NDP or the Elizabeth May Green Party?"
The point is most people don't vote for a party anymore, they vote for a leader and if you tied the leader to the party, it might show the Tories doing better than current polls indicate.
Just a theory.