Another vote for "The Band Played Waltzing Matilda." But for me, there are two I've encountered in the last few years that just leave me choking on tears. One is David Roth's "Manuel Garcia", which I first heard just after losing a beautiful family member too young to cancer. The other is "Touch a Name on the Wall" by Joel Mabus, which I've known for a few years, but which I just heard him perform live for the first time last month.