I know that the movie took some pretty great liberties with the actual historical event, but even so, it is good for our abysmally ignorant teens to see something that reminds them that strength, honor, and courage are timeless virtues, however much they seem to be lacking in this day and age.
I don't consider 300
to be at all historically inaccurate, at least in the usual ways. The film is told from the perspective of an orator, and as such, is appropriately embellished and jingoistic. Xerxes' monstrous stature is one of the more obvious examples, but there are many. As for the aspects surrounding Sparta's precise role in the Battle Of Thermopylae, I believe the movie's representation to be in accord with what the orator would have understood
them to be. Propaganda played an essential role in war then, just as it does now.
The film's portrayal did cause quite a bit of confusion among viewers, though. My little sister and her friends, "abysmally ignorant teens", misunderstood the history as a result of the film. One of them somehow confused Xerxes with Darius the Great! I was more surprised to find that none of my friends enjoyed it at all. Not a one. It seemed those who were more or less familiar with ancient Greek history thought the film took too many liberties, and those that didn't know Greek from go-go felt it was too cryptic to follow. Personally, I loved it and will purchase the director's cut when it is released.