I am not a big fan of Captain America because I'm not familiar with many of his story lines. What I know from the trailer is this: A scrawny WW II soldier gets juiced up, given a shield by a woman that he will fall in love with, and dressed up like an American flag. There is also a guy with a red skull that is some how involved with Hitler.
This movie is going to be a much harder sell than the other Marvel-based movies. With Thor, you were guaranteed a good CGI light show with scenes from Asgard. The X-men already had a movie fan base to work from. Iron Man would be the closest comparison one could make, but it was fun watching Robert Downey Jr. have fun in each situation because that is how the character was designed. How fun can a World War II drama be?
Captain America is basically Marvel's version of the Blue Boyscout except without the cool powers and back story. I would also like to lodge a complaint with Marvel for trying to shoe-horn love stories into their movies. DC is really no better, but I still expect some more more well-rounded female characters as it creates more movies leading into the the Avengers movie (though I did like Sif).
Alright Captain America fans, put down your Friendly's Captain America ice cream and star-shaped donuts and get to a keyboard. Your assignment: Convince this cynical user that seeing this movie will be worth the price of admission.