Karl Lagerfeld, obviously! I don't want to sound like some crazy fan of his, because I do admit he has weaknesses, but I think that he is incredibly talented. Even with his old age, he's still releveant, always bringing something new to the table.
But even more importantly, Lagerfeld's couture is wearable and innovative. He doesn't dress models in period costume every season. He takes a part of the body to accentuate, and makes the woman more beautiful.