Earlier this month the Hoover Institution Archives released ten previously obscure photographs of the aftermath of the Hiroshima bombing of 6 August 1945. Most of the publicly available images of post-blast Hiroshima are either antiseptic pictures of the ruins or photos of the burns suffered by survivors, which, while impressive (or gruesome), don't convey the full extent of the carnage. The new photos, which were found in a cave outside the city by American GI Robert Capp, remedy this omission - to say the least. The pictures are very graphic and not for the easily depressed or faint of heart, but if (like me) you have a morbid fascination with nuclear war they can be seen here.
If you prefer a more esthetically pleasing nuclear holocaust, these photos of the French Licorne H-bomb test of 3 July 1970 might appeal. This was one of the largest French atmospheric nuclear tests, and an observer commented at the time that it was "stupendously beautiful." Which is, I guess, what the French look for in a hydrogen bomb.
And if you prefer to look on the lighter side of nuclear war, you could do worse than check out the (slightly dated) Flash animation The End of the World. You'll need a Flash player for the video, and a tolerance for four-letter words. (Though, if you don't mind the idea of nuclear annihilation, a little profanity probably won't bother you too much either.)