Aaron pointed me to this excellent FAQ on the Japanese reactor situation, over on (of all places) the Something Awful forums. You have to click through an annoying ad to get to it, but it's a fine, calm discussion of what's going on there, and what the actual risks are.
I will admit to very mixed feelings -- horror for the people living nearby, annoyance at the fact that this will likely hobble nuclear power for at least a decade, and hope that, when the industry does begin to recover, it might motivate people to use more modern and fail-safe nuclear technologies. Yes, I'm mildly in favor of nuclear power as a component of the overall electricity mix, but only with a much more careful choice of reactor designs...
Let us step back for a second - those reactors took the 4th/5th largest quake on record (more powerful than the eruption of Krakatoa) and the resulting tsunami, with their containment vessels intact! So far, radiation leakage has been limited. That's pretty outstanding design, in my book.
And those were old reactors, due to be retired this year. Not even the newest design, techniques, and materials available.
It is not realistic to build reactors that can really take anything that could be thrown at them - the cost would be prohibitive. When building anything, there's a balance of cost vs risk.