Who's your favorite Fashion Designer?

I wanna know all about your favorite designers. Tell me who they are, Why you like them, and your favorite collection of theirs. Please tell me high fashion designers. No JC Penney or Kohl's or stuff like that please. Thank you Fashionistas!
Update: Thank you guys sooo much for your answers so far. It's wonderful that all of you like so many great fashion designers. My favorites are Alexander McQueen and Vera Wang. I also love Oscar De La Renta.
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