Being born at the very beginning of the 1970's it's a war most people of my generation probably know very little about. It's not like the World Wars that get taught in most schools - especially the history behind ANZAC day (which is on April 25th).
It's more like the Korean War, except without the comedy of TV shows like M.A.S.H. to popularize it in modern culture.
The most my generation really knows about the Vietnam War (unless they've actually done research) is that it was a massive failure for the U.S.A. and by default Australia. People protested it. There's was some chemical called Agent Orange that was extremely toxic to just about everyone and that many war heroes in movies claim to have "...fought in 'Nam".
There's also been a few Hollywood movies specifically about Vietnam, such as Oliver Stone's, Platoon, and probably the most famous of them all, Francis Ford Coppola's, Apocalypse Now. Neither of which give much insight as to what the war was really about since they focus of stories within the war rather than the war its self.
I'd always thought that once Western forces moved out of Vietnam that was the end of it but recently learned from an interesting documentary, Operation Babylift by Vietnamese refugee, Dai Le, that the war continued for another two years with South Vietnam eventually falling to the North.
I also learned from the same documentary (not surprisingly since this was the film's focus) that about 3000 Vietnamese Orphans towards the end of the war were airlifted out of Saigon orphanages and delivered into the arms of waiting couples in the US, Canada, Britain, Europe and Australia. It was apparently one of the biggest adoption programs ever undertaken in history (and I'd never heard of it?).