I'm kind of amazed that in this Whedonesque age of irony and being too cool for the material that you can have a movie this old-school, sentimental, and idealised, but I'm damn glad they went in this direction with it. Hard to believe Chris Evans was the same jackass who played Johnny Storm in those two Fantastic Four movies everyone collectively forgot about (seriously, no one talks about them) because he's really damn great as Steve Rogers here.
There's also tons of fan service if you know your 40's era Marvel (seriously, Roy Thomas' head would explode upon seeing it)--they even pay homage to that stupid TV movie in one bit. There's also a lot of crackling dialogue, tons of cool fights (let down a bit by the CGI in places--it was somewhat glaring in 3D, maybe less so in 2D) tons of gonzo Nazi/HYDRA tech, and and honest-to-god musical score as well (Told you it was old-school) The wartime poster credits were awesome as well.
I have to say, that while I liked Thor and liked how it really sold Asgard as a real world, but I think Captain America edges it out a little more in terms of being a more completely entertaining movie. Then again, I'm biased, as I really liked The Rocketeer (directed by the same guy) and this works in that same quasi-retro vein.
The trailer for Avengers at the end? Well . . .it made me plan to see it, so I guess it worked.