How historically innacurate do you mean?

Of course, they don't know about everything that happened or whatnot, and at best it's their "idea" of what happened, but I'm pretty sure that there was actually a King Leonidas who stood up to the Persian Army with only 300 men.

That said,

I adored this movie. The cinematography was incredible, and hey... nothing wrong with watching incredibly buff men run around in loincloths for 2 hours.

Great, great movie. I'll be seeing it again!