I'm not a big fan of Nuclear Disaster films. If you'll all pardon the pun, they radiate little charm.
For that matter, end-of-the-world scenarios aren't that exciting any more, even when the horrible end is averted. They've become so predictable. The clock is ticking, always in a red LED (a Roger Ebert reference). The hero, who is always the fellow everyone has been scoffing at since the beginning of the film, and who alone has to save the world, finally pulls the proverbial rabbit out of the hat, thwarting the plot by pushing the right button or masterfully sending the master computer with a dizzying display of contradictory logic. It's all become hopelessly cliched.
Even the Bond films, a cliche unto themselves, have fallen into disrepair, and they're supposed to be all about this scenario.
I will admit, the idea of Earth's end as proposed by Douglas Adams in The Hitchhiker's Guide to the Galaxy is amusing, but if I go any further someone will accuse me of giving spoilers.