"So nothing's really green. Does that mean it doesn't matter which source we choose?"
Are you missing the point on purpose? Nuclear energy isn't "green" simply by not releasing co2 during power production, it's a polluting as oil or coal, in that all release long term toxins into the environment, both during the extraction of energy (mining/drilling) and as the result of failures of infrastructure (oil spills, rail disasters, plant melt downs) Solar and wind are both safer(in that failures don't damage large areas) and are less responsible for toxic by products in manufacture and operation.
Once again, fuel(oil, coal, natural gas, plutonium) get's used *once*...to keep making power, you need to mine more. Solar, wind, hydro, geothermal, once the infrastructure is built, no more toxic fuel needs to be mined to keep making power. Maintenance, replacement, sure. But that's clean compared to mining/drilling/transport of fuel.