We'll see, but I put Mr Singh's chances at even forming the opposition as pretty low right now. Like it or not, I don't think that most Canadians are ready to vote for a religious sikh (especially in Quebec, which is critical to the NDP). 

The NDP card carriers may like him and think they are being bold and "progressive", but they are pretty far removed from most mainstream Canadians. However, I do expect the NDP to suck up quite a bit of the progressive vote in TO and places like Vancouver/ lower mainland, to the detriment of Mr Sunny Ways. But still they'll likely be a distant 3rd Canada wide.