There will be celebrations, but it strikes me as anti-climactic. Lucky timing for the new government, though; its way too soon for it to have to wear any of the failure. Whereas this decision will be the big fat fucking failing cap-stone to the too-long-but-now-ending political career of Stephen Harper. And I think Justin's nominal pro-Keystone stance was quite clever. It was a bit like supporting the continued existence of the sun and the moon. It ain't up to you, so why not? But why not go the other way a la Mulcair? Well, there were potential votes out West to be harvested for being a least a little "pro-pipeline", and support for Keystone could be used as a vote-harvesting carrot, even if it was a carrot made of smoke and mirrors. Mulcair refused to wave the fake carrot, and lost. Not that this was the sole reason he lost. There was also that increasingly tattered looking beard.
Anyway, going forward, I'm betting against Northern Gateway; I am inclined against Trans Mountain; and I suspect Energy East will pipe oil (or whatever) one day.