here are my suggestions: (basically all are repeats but they need to be in our repetoire!!)
obvi "Waiting on the World to Change" - John Mayer
"Peace Train" - Cat Stevens
"Long Way Around" - Dixie Chicks
Something Jack Johnson - i know it sounds weird but he has some great stuff with good meanings behind them..."Crying Shame" "Good People" "Traffic in the Sky"
Kiss by a Rose - Seal (ok so i know its not "feminist" but seriously listen to the song and tell me it wasn't MADE FOR A CAPPELLA)