Two great songs that I haven't seen mentioned on the thread: The Malvinas (Dave Rogers) & Ghost Story (Jim Woodland). These are both about the Falklands but certainly cover universal themes. Roy Bailey does a brilliant job of both of them (as he does with most things).

Otherwise No Man's Land and The Bands Played Waltzin' Matilda. Eric Bogle's own versions please (though the version of Waltzin' Matilda that started the thread by the Pogues is also pretty good)

For something new which addresses Iraq have a listen here:
To Be A Soldier