I suspect that in the wake of the recent election outcome the arena is wide open for the Conservative Party of Canada.
There are three reasons for saying this.
To start with, the voters of Ontario have clearly made the decision ina sizable enough number that Stephen Harper and the Conservatives aren't as intimidating as they were in the past. This is very important. The East and Central Canada has never really understood or identified with Western Conservatives, and have feared them as a result. This long hurt conservatives at the polls.
The second reason, and perhaps the opposite sdie of the same coin, is that the Liberal party has lost its iconic brand quality. Die-hard Liberals may deny it, but realistically political parties are vehicles to gain power. For members of a political party, if the vehicle doesn't take you where you need to go it has no value. For voters, if the party doesn't deliver what you want, it has no value. This is the current state of the Liberal Party of Canada.
The third advantage on the ground for the Tories is the much remarked NDP spike. Without taking anything away from their success, it was a really only a flood in Québec. Outside of la Belle Province the Conservatives picked up more seats, and where the New Democrats did win outside Quebec they did so in areas that are really pretty NDP freindly.
The New Democrats have now been given what they asked for, and that particular gift is not always ass nice in reality as it was in anticipation. They are now dependent for power on Quebec, not on the the rest of the country. Their caucus will undergo a huge power shift. Old NDP warhorses will be pushed, at least partly, to the side, to make room for Quebec priorities. If the party doesn't pay attention to the hopes of the Quebecois their seats will either go back to the Bloc (or its next incarnation}, or to a re-emergent Liberal party. (They could just as conceivably go to the Tories, but we'll address that a little further along).
The Tories have two options in Quebec. They can either fight the NDP over Quebec, or they can decide that Canada has returned to a nation of two solitudes. The initiative lies completely with them.
If they determine to turn the nation to two solitudes they can easily play at being decent without genuinely satisfying Quebec's problems. Mr. Layton and the New Democrats will need to become the spokespeople for Québec and offset the Tories on Québec's behalf. Its likely that the NDP will appear to be, in varying degrees, pro-separatist, champions of special status for Quebec, and socialists demanding more pork from the rest of Canada. That's not an easy sell outside of Quebec, and its almost a necessary sell inside Quebec.
In the event the Parti Quebecois wins the next provincial election they will definitely add their shrill voices to Jack Layton's. If that happens it will cement the Conservative position outside Quebec, provided the Conservatives really seem to be to acting within reason. They have already demonstrated this is possible. (Remember, they don't have to convince Quebecers or leftists that they are reasonable - they just have to convince the center of the natiaonl spectrum that they are, and they're already well down that road).
This leads toMr. Harper's second alternative. Quebec can become a front line in the battle for votes. After all, the Tories have nothing to lose by going to war over Quebec. Any vote they win they win from the opposition. Its a zero sum game where they have nothing to start with. Every change is a gain. What's more, they earn these victories by tempting Quebec back to the national conversation, and so solidify their appearance as reasonable people.
Brian Mulroney demonstrated that there are Quebecois nationlists who are comfortable being right of center. His trouble was that he had to reconcile Western conservatives with Québec separatists. His majority depended on that. Trying to change the constitution meant special treatement for Quebec within Confederation. Doing that alienated traditional Western Tories then (and would do so even more now), and led to the rise of Reform and the Bloc, and the self-destruction of the Progressive Conservative Party.
Today the Tories don't need la Belle province, and so enjoy an advantage Brian Mulroney didn't. TheTories don't need to reopen constitutional debates. They can just speak truth to Quebec's power, explainign that the times have changed. Québec's best chance for peace, stability, economic advancement and achievement of its aims and financial benefit from Canada lies with having influence inside cabinet. A socialist/separatist Quebec won't hurt the PM. In fact, it will help him by giving him a vulnerable target to marginalize.
All this depends on the Prime Minister being smart. He can start with the recommendation made to many socialists: have a hard head but a soft heart. A gun registry can be killed on the basis of cost, as can vote subsidies. Mr. Harper has no problems appearing competent on these files. Where he suffers is the perception (likely inaccurate) that he is mean.
Recognizing a nation within a larger nation is soft-hearted, reasonable accommodation. Allowing addiction workers to maintain safe injection sites despite disagreeing with them is indication of respect and a soft heart. The costs are low, and the pay off from to opposite course of action isn't valuable.
Honouring our committments to allies Its received wisdom that Quebec is anti-military and against the war in Afghanistan. It is a hard fact that the storied Van Doos are a Quebec regiment with a proud martial history. They are serving honourably in Afghanistan right now, and the Canadian Armed Forces have a large number of Quebecois among the ranks. It should be easy to nail the NDP on the conflict between being non-militarist and pro-Quebec and dimissing the importance of Quebec's strong military strain. Providing other soft nationalist gains can further marginalize opposition parties.
All in all, the future looks bright for the Conservatives, and dark for the Bloc and Liberals. Even the NDP has an uphill battle. Canada's political landscape has indeed changed.