This is a great thread, nice to see it resurrected.
My recommendation would be one that should be mentioned in the same breath as Alas, Babylon or On the Beach as a classic of nuclear war/apocalyptic literature: Level 7 by Mordecai Roshwald-
''Level 7 is the diary of Officer X-127, who is assigned to stand guard at the "Push Buttons," a machine devised to activate the atomic destruction of the enemy, in the country’s deepest bomb shelter. Four thousand feet underground, Level 7 has been built to withstand the most devastating attack and to be self-sufficient for five hundred years. Selected according to a psychological profile that assures their willingness to destroy all life on Earth, those who are sent down may never return.''