Great idea, instantly recognizable to most Americans I imagine. Seems washed out a bit, could use some more contrast, and might be better if the sides of the letters were parallel to the sides.
I like the angle you used for the photo. Gives it a lot of interest. You can see the indention of the inscriptions in the monument. I wish that the contrast was tweaked a bit more to really bring this out. You could really bring out the shadows of the inscriptions and they would really pop out of the picture.