Okay, this might take a bit of stretch for both Canadians and USA'ers but here goes why the Keystone pipeline was a good idea.
It doesn't make sense to refine a product thousands of miles away from the market and then truck or train it to the market in its various commodities. That is, gas, diesel, propane, bunker fuel, etc. Each product needs a different mode of transportation. It makes more sense to pipe the raw product to the market, refine it and then distribute it locally.
Regecting the project for environmental concerns, simply doesn't make sense, because the USA does not have a very particularly stellar record when it comes to protecting the environment. I point to the fiascos in Alaska and the Gulf of Mexico. Although Canada has no such record, it seems that the Canadian environmentalists are over-emphasizing the dangers of the pipeline.
A few jobs in Canada and tons of jobs in the USA. Seems good to me...