300 is an awesome movie. As Timeshredder notes, what you primarily get when you go and see it is a visual feast, not overly stylized but definitely blending into the realm of the fantasy epic. It's not a documentary. And yet, like the historical event it's based upon and is largely faithful to, it is very moving.
The story, briefly, is this. (Spoilers follow.) The Persian Empire, led by Xerses I, seeks to invade Greece and make her city-states its vassals. Xerses is motivated by a belief that he is 'King of kings', a desire to secure the unprotected western flank of his Empire, and a further desire to succeed where his father, Darius, failed. As the Persian horde approaches, Greece is divided against itself and unsure of whether to fight. The Spartan King, however, has only one mind where they have two, and he leads an eponymous force of three hundred to face the Persians. After a bloody fight in which they exact a high price from the Persian armies, all are killed; but this sacrifice inspires all of Greece to unite against the invasion, which is eventually repelled.
It somewhat misses the point to say that this movie omits to mention parts of Spartan society which we today find deplorable, such as slave-owning, or to say the dialogue contains "Bushisms". The viewer can make their own mind up if the harsh, militaristic Spartan society which is portrayed, especially in the first quarter of the film, is to their taste - they will likely conclude it is not. This doesn't undermine the central message which the film unintentionally portrays, which is that our conception of the good life - whatever that may be - sometimes requires sacrifice to defend it.
Nowadays, such sentiment is often regarded as parochial and backwards. Maybe I'm not helping my case by supporting it with an example from over two thousand years ago. This, I am sure, is undoubtedly why the film has been described in some quarters as fascist - an over-used label. Three hundred men choosing voluntarily to sacrifice their lives in defence of their homeland and the ideas encapsulated therein is, of course, not remotely fascist; it is a measure of how low our discourse has got that it could be considered as such. Nor do comparisons between fascist societies and Sparta as depicted in this movie hold any water. The Spartans may be militaristic, but they are acting to defend themselves, not claiming the right to rule over other peoples, which is the essential element of any group worth calling 'fascist'.
It is only the lack of an organized threat to the existence of our societies that makes us become blind, perhaps even hostile to, the plain fact of reality that sometimes sacrifice and the encouragement of virtues not usually associated with these societies may be needed in their defence. Patriotism and the sometimes simple-headed defence of what is ours - defending it from attack, not inflicting it on others - are underappreciated virtues.
Twentieth-century blood and soil nationalism and fascism made us weary of people who come wrapped in the flag, and rightly so. But it's quite easy to see how it's possible to take this all too far, to declare that all is relative and hence nothing is worth defending. 300 is rousing precisely because it portrays, clear as day, a situation in which we can see that the exact opposite is true. It's beautiful in its moral simplicity in the same way that the story of anti-Nazi partisans is, or the Star Wars series was.
The virtue of this film lies in its portrayal of this morally simple situation. I honestly say this without reference to any actual event happening in the world now, and certainly not in reference to a crude analysis of this film as some sort of depiction of the "clash of civilizations". That's not what this is about. What it's about is the fact this film stands out as a wonderful story about sacrifice and hardship endured in pursuit of an ideal, which is not a story that we come across often now that we've entered the End of History. The comfortable existence we now experience has liberated us from the constant struggle for survival which has characterized all of human history until so very recently. In such a state, we would do well as a people not to forget the lessons and example that this historical event sets for us. We may need these virtues again one day.