It's not necessarily a propaganda film, but I would most definitely say Band of Brothers; though it is a mini series.

However, I would say that the most 'patriotic' film I've seen recently was Flags of Our Fathers; I thought it was alright, but I'm sure Letters from Iwo Jima is better, though it's not American propaganda.

Generally though, the more 'patriotic' a film is, and the more closer it is to straight 'propaganda', usually it will end up being worse proportionally. I think really the only propaganda film that pulled off being of cinematographic worth was The Battleship Potemkin, though that was Russian.