Seriously, after just two and a half minutes of this trailer, I have a totally clear idea of who Steve Rogers is, and why he's special. And why he deserves to be Captain America. And what this movie's really about.
The new trailer for Captain America: The First Avenger promises a lot of flag-waving and nostalgia for the time when Americans believed in self-sacrifice. But it also promises a real heroic journey, for a genuine non-emo hero. The trailer suggests that Steve Rogers' arc is the opposite of Peter Parker's — he doesn't become Captain America and then learn responsibility, he becomes Captain America because he's eager to take on responsibility. The bit where everybody runs away from the live grenade except Scrawny Steve is especially great.
If the actual movie does half as good a job of selling us on Steve and his eagerness to give his life for his country, then it'll be light years ahead of some other recent superhero films. Fingers crossed!