Bieber: One Million, Its a young modern scent. And it's flashy. The fragrance projection is high, and I'm sure he wants to have even more attention. I believe its fitting.
Phelps: Anything aquatic, hmmm Have to say Acqua Di Gio. Or Cool Water.
Gates: Gates has said many times he loves the outdoors in articles. He owns a mansion in the hills of Washington state. So I would say GIT, being that its a clean fresh green scent.
Obama: Creeds Aventus, This fragrance has become a iconic static symbol to many. So this is fitting as president.