I'm Canadian, so American patriotism (or not) doesn't really touch me. But when I saw this video of God Bless America, it did touch me. The author, Irving Berlin, sings his song with a children's choir on the day he turned 80 (1968):
I've heard this song many times, performed by many popular singers, including Celine Dion, but this is the best interpretation for me.
What is interesting, Berlin refused to benefit from this song. After the first performance in 1938, he said he couldn't accept money for his patriotism and sighed up all the proceeds to some charity. I think it was Boy Scouts of New York but I'm not sure. Whatever that organization is, the arrangement is still in effect. That charity is quite rich by now.