Today's news claim that "a serious nuclear disaster threatens the Earth", things look real bad.
I'll make another threat to the Earth: behave, or I'll kick you! Who gave the permission to move Japan 2.4 meters to a wrong place? Now people will crash to traffic signs if they trust their satnavs.
But other than that, I fail to see what's the big deal. Sure, not having any radioactive leakage would be preferable, but the damage caused by leaks at the Fukushima plant are a fairly minimal aspect when compared to the immense destruction caused by the tsunami itself - even if the damage escalates from today, which is not that sure.
If anything, I think this shows how safe nuclear power is. For me, the question was resolved at Chernobyl. Even if you have a large nuclear site, designed for production of nuclear weapon material as a by-product of energy, with a completely reckless and incompetent leadership screwing things as bad as is humanly possible (here I'm not talking about many of the brave firefighters and soldiers etc who worked there, just the leadership), the damage was less than spectacular. Sure, there was a sizable radioactive leak which is easily measurable far away, including where I live - radioactivity is always easily measurable. Areas around the town were deemed uninhabitable - although at the same time, this created a rather interesting nature reserve.
But the damage is minimal when compared to the impact of mining and burning coal (excluding any impact of CO2 emissions, just considering the mining accidents and the particles and radioactivity emitted from burning), or the impact of collecting wood and burning it, or just about any alternative.