This is the 2nd famous design for the Obama campaign done by Shepard Fairey (the first being the official 'O' logo by VSA Partners). What's interesting about this particular photo is that the Obama poster is right over a poster by Mear one. Shepard and Mear had beef a while ago (check the Supply and Demand book for details).
I forgot where I read it, but someone mentioned originality not as being the first to do something, but as doing something that no one else can duplicate. No one is even coming close to David Choe's style.