Dude, one title absolutely heads up the list:
Earth Died Screaming by Tom Waits
After that, it becomes a question of thematic songs for the End of the World, or musically fit songs that properly convey post-apocalyptic asthetic?
London Calling - The Clash (thematic and musically fit)
Corona Radiata, Ripe (with Decay) or Me, I'm Not (the 14 min long version) - NIN (for musically fit, thought not thematically fit)
The Day The World went away - NIN (thematic)
After the Gold Rush - Neil Young (Thematically & Musically fit?) - and arguably the #2 to Earth Died screaming
both thematically and musically i guess. my list was a mix of that as well.
i have listened to all of the suggestions so far. good choices all around. some very dystopian sounding pieces, a number of heavier 'moment of destruction' songs and a few somber "hymn for the dead' style songs. thank you everyone.