Imo the most important (in any way) designers ever, are these three:
Cristobal Balenciaga - He was the best leading
French fashion designer, which is quite something considering the fact that he was Spanish. He was known as the couturier of couturiers and Coco Chanel once said about him:
"Cristobal Balenciaga is the only couturier able to design, cut, assemble and sew a dress together entirely by himself."
Gabrielle "Coco" Chanel - She made
practical and comfortable clothes popular (like pants and little black dresses). And of course the all-time classic Chanel accessories, multiple strands of pearls, gold chains, handbags with shoulder straps made of gold chain and gardenias. Also she was the first one to make designers super-stars.
Christian Dior - He was the one who helped to re-establish Paris as the capital of world fashion after the war. Known as the last dictator of style in the 50's and for his theme-collections (ballerina skirts, classic suits, A-lines). Marketing surveys have shown that Dior is the most widely recognized brand in top fashion to date.
Other designers known for their contribution to the fashion world (imho
Calvin Klein: He was the pioneer for the minimal chic,the infamous "less is more" and gave birth to the designer jeans and more affordable lines (ck).
Widely considered the most prominent American fashion designer.
Ralph Lauren: Known for being one of the most innovative designers, the epitome of classic fashion and for his "power suits" and preppy look.
Gianni Versace: The word "flamboyant" was created specifically to describe his work. Striking colours, materials, and cuts. His collections for men and women were sexy to the point of vulgarity. Gold, Glamour, Dazzle. He "created" today's extravagant D&G, Roberto Cavalli, etc
Vivienne Westwood: She played an essential role in the emergence of Punk Rock in the 1970s and she has become one of the most influential designers. She uses british fabrics such as harris tweed and tartan and garments such as the corset and crinoline.
Hubert De Givenchy: His mentor was Cristobal Balenciaga. During the 50s and 60s Givenchy was extremely popular, because of his elegant and refined designs. Audrey Hepburn (who can forget the Breakfast At Tiffany's stunning black dress?) and Jackie Kennedy represented the Givenchy woman. At the J.F.Kennedy funeral all the Kennedy family was dressed in Givenchy clothes imported from Paris.
The most promising fashion designers nowadays are
Olivier Theyskens and
Nicolas Ghesquiere.