We watched "Captain America: The First Avenger" last night - only backdraw with this film would be that it's overly 'american' at times. But apart from that it's a more than decent super hero story.
Big bad evil forces ("Hydra", working under the cover of WW2/the Nazi army) had to be beaten for the world to survive.
But apart from, or rather despite the 'americanism' I really enjoyed the film. It's an 'easy watch' type of film and I'd be tempted to watch it again if I was in the mood for the full storyline of "The Avengers". :-)