The Things They Carried
My knowledge of the Vietnam War comes from mostly:
Graham Greene's The Quiet American, which Greene wrote before the U.S. presence in Vietnam was ramped up and everyone but him was distracted by Korea.
Michael Herr's Dispatches, a journalist's memoir of covering the war.
Forrest Gump, which I saw most recently in early fall of '04 in the witness room of the courthouse in downtown Baltimore and which I believe may be playing on a continuous loop in that sad sad room.
The soundtrack from Miss Saigon, which my parents went to see sometime in the '90s, whenever it was the big musical to see.
Tim O'Brien's The Things They Carried.
Dispatches and The Things They Carried are the most powerful, with the edge going to The Things They Carried because a journalist can always get out or move around or take a vacation in Saigon.