Both are iconic songs and videos from the respective artists and definitely the magnum opus of their careers, altough I'd change them both for Oops and Crazy In Love, they deserve it more
...BOMT is both the more iconic song and video. Everyone knows the song from the opening chords alone.
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People turn up on the first note of Single Ladies before Beyoncé even open her mouth. This statement was utterly pointless as both videos are iconic.