I love fashion designers from the 20's and 30's. In my eyes, they started modern fashion design as we know it. But Elsa Schiaparelli was one of the world's leading fashion millinery designers. Her designs were bold, bright and every now and then, broke the rules on design. She worked with Salvador Dali, Mae West , Greta Garbo and other famous people. Months ago, I was lucky enough to find one of her straw hats, in mint condition. The techniques used and craftsmanship were beautiful. I'll try to upload some photos of this beauty to share.
Elsa Schiaparelli is also one of my design heroes - I'm reading her autobiography at the moment and it's fascinating.
In terms of contemporary designers, I love Piers Atkinson's work, and I'd have to give Chloe Scrivener a mention too - she taught me millinery at the London College of Fashion, and is not only a talented milliner but a great teacher with endless patience! http://chloescrivener.co.uk/