Is it "Nasty" with iconic quote, "Rhythm Nation" with killer MV and choreography, impactful and her best song "Black Cat" , her biggest US hit "That's the Way a Love Goes", her biggest WW hit "Together Again" or collaboration with her brother called "Scream"?
Before ATRL, I only knew "Together Again" & "Scream", but it seems ATRL usually choose "That's the Way a Love Goes" as her "signature song".