With McKenna out of the way and the second week of leadership speculation calming down somewhat, there is time to look to an obvious choice for leader:
Stephane Dion.
The only issue I'd take with this endorsement from the Draft Dion blog is that Dion would not defend the Trudeau vision of Canada. Rather he'd represent a vision of Canada which a great many Canadians share and which is sadly not being reflected in the current dialogue.