That is some opinion for never having seen the movie.
Molon Labe!
In 480BC, the Persian Empire with the most fearsome army ever seen to date, began its conquest of Greece. With 600,000 men, battle-hardened and cruel, King Xerxes began his advance towards Athens expecting little resistance. From the north coast they began, and slaughtered all in their path.
King Leonidas of Sparta took up arms in defense of his Neighbors. With 300 hand picked body guards, 700 Thespians, and 5,000 Greeks; King Leonidas took up position at the Pass of Thermoplyae, the only direct route through the mountains to Athens.
At the approach of King Xerxes army, an emissary was sent to King Leonidas seeking his surrender. "Why die here? We are a host without equal... Our archers are so numerous that the flight of their arrows darkens the sun..."
King Leonidas replied: "So much the better, for we shall fight them in the shade!"
King Xerxes began his assault and the Greeks ran. At the bottom of the pass, Xerxes offered surrender to Leonidas, that if they would lay down their arms, their lives would be spared.
"Molon Labe!" Cried Leonidas! "Come and get them!"
For three days the Spartans fought, and when the battle was ended the Spartans were killed to the man. But the time afforded to the Greeks to raise an Army allowed them to fight and eventually turn Xerxes from Greece.
King Leonidas and his 1,000 had won!
Today a stone memorial can still be found in the pass of Thermoplyae that reads : "Go tell the Spartans, travelers passing by, that here, obedient to their laws we lie."
As me me seeing the movie, I doubt that I will. I usually wait until it hits DVD to consider seeing it as then I can use the subtitles to understand what everyone is saying.
They just had a history channel documentary on it, and it seems your tale is a little off. In actuality, the Persians would have waltzed right over Greece, but one Athenian, Who was in charge of their fleet, formed an alliance between the different city states and organized a Land army along with the Athenian Navy. It was his military strategy (as opposed to Leonidas's tactics) that won the war. Though most Greeks did not agree with him at the time, he believed that the Persians were NOTHING without their armada of ships to back them up, support them, and aid them.
On the first day, Leonidas led the ground troops at Thermopyle composed of some odd 7000 Greeks and Slaves. Anotides(not certain that's the spelling or how you say the Athenian name) blocked the strait to prevent the Persians from bringing in reinforcements OR from having their massive navy support the Persian Army. Anotides held the Fleet off for 2 days. This prevented the Persian army from flanking Leonidas's army, by bringing in an army on both sides of the canyon.
However, on the third day the Persians figured out how to get troops to the other side, and the Greeks knowing tactics knew that once the Persians did this, it was only a matter of time till they lost this battle. If they were all killed here, they WOULD lose the war. Knowing this, Leonidas sent the Greeks away to gather even more strength and to continue to do battle in locations where they might win. The Greek Navy also retreated. Leonidas was left with 300 men. He fought a delaying action so that the Greek army could actually get away instead of getting slaughtered. The biggest miracle of the 300 then wasn't the battle previously (which still was a pretty great miracle, in that 7000 greeks held off an army numbering anywhere from 200,000 to a million men) but that 300 actually delayed that army long enough for the rest of them to get away.
However, the Persians ONLY lost ~20,000 men. A great deal more than 300, BUT a small dent in the Persian army, and something they could easily afford. The Persians then proceeded to Athens. The Athenian Admiral tried to convince them that they needed to flee Athens, and that their best hope at this point was by sea (where his ships were only outnumbered by a factor of 5 to 1 instead of the land armies which were outnumbered by a factor of 20 or 100 to 1. Those who relied on the land army, were slaughtered when Athens was razed to the ground.
The Athenian Admiral then took on the Persians at Salomina (sp?)where one of the greatest military victories ever was accomplished. He took on the Persians at sea, and won...springing them into a trap...and pushing them back. At that point, they had a choice of either being deserted without supplies in Greece, or taking what scraps of a fleet they had left, and limping back home. The Persians left and the Greeks won...leading to Athenian dominance in many ways of the Mediteranean, and the seeds of Democracy being sown around the known world.