From what I have read, "We Were Soldiers" portrays it pretty accurately. I agree however that most Vietnam movies rely too heavily on the criminal American soldier.
I'm surprised no one has given kudos to Gene Hackman, Sly Stallone and Chuck Norris for all those POWs they liberated in the 80s.
Missing in Action II is a cult favorite of mine, Soon tek Ho dressed in a japanese uniform (it was supposed to be vietnamese, but I guess the movie company didn't have those) vs Chuck Norris, still kicking ass after a decade in camp!
I guess out of all of them, First Blood is a favorite not so much because of the Stallone movie but because I'm a huge David Morrell fan. Even though the movie doesn't really compare with the book, it couldn't even if it tried. The movie came out in 1982, well after Vietnam whereas Morrell's book was written in 1972 during the height of the anti-war movement in America. The ironic part is that in the book, Teasle and Rambo have a mutual respect for each other even though they are doomed to fight and kill each other (Trautman is the one who actually finishes off Rambo after Teasle wounds him).
First Blood the movie was a very toned down version of the book. It wasn't until the very last installment of the movie series, Rambo, that the very essence of David Morrell's original character was finally captured on film.
As for the military accuracy of the first three Rambo movies, well, they make me giggle.