Like i said earlier. "300" just looks good. Meaning visually. If it weren't for it's visual look, it would've been a normal epic movie unlike the sweeping "Gladiator" or the monumental "Braveheart"
Seriously, ok imagine "300" visually looking like a regular movie, no graphics. Cut out all the CGI and look at it with just the standard movie camera look. It'd be a mediocre movie. "300"'s visuals carried it all the way. And as fantastic as the movie looked visually, entirely candy-coating the normalcy of the movie with CGI won't help it's story. And just like with video and PC games, graphics don't make it what it is. Content does.
I did like Xerxes and Golum on steroids characters though.