We can't yet say that the Ontario political landscape has changed: the Tories are probably still the Natural Governing Party of Ontario, just as the Liberals are federally. Fingers crossed that will change (in Ontario - not federally), but a few years of Liberal rule isn't enough to do it.
So complacency is not the appropriate order of action for Ontario Liberals. (Although a new holiday is a very nice way to celebrate, so thank you, Dalton!)
What I propose is that McGuinty reach out to the NDP. I'm tired of vicious bickering between the NDP and Liberals, two parties who have very similar values and goals.
Many NDPers are strategic voters, voting Liberal when necessary to defeat a Conservative. So the Liberal party should give some support to the NDP in return. Help Howard Hampton bring some reforms to the North. Ask for his advice. Enlist Hampton's help in dealing with the crumbling manufacturing sector. All these things would help Ontario. Maybe McGuinty could go further... Give the NDP official party status. Put an NDP MPP in cabinet, or give them a big policy appointment. Forge allies. Make a coalition.
The NDP, at its best, is the conscience of the province. And the left in Canada is split, now, between three parties: the Liberals, NDP and Green (although the Green party is just posing). That leaves the Conservatives in a very powerful position. I'm not suggesting that the Liberals and NDP should merge, but some cooperation is appropriate.