I can't tell from the posting if the questioner is British or American. If it is the latter, the most successful and rousing chorus songs are Spirituals and Gospel Songs. "When The Saints Go Marching In" is always a winner but, if you are looking for something a little more esoteric, you might try "I'm On My Way" or "Come And Go With Me To That Land" (They are, both, parts of Odetta's "Freedom Trilogy). If you want to do an anti-war song, you could do a lot worse than to choose "Down By The Riverside" (I ain't gonna study war no more.)

                      Mike