Ooo tough. Between Count Von Lagerfeld and Miuccia Prada. Whilst the Count would be jokes and make me more like the Olsens', Miuccia seems like she would be more fun and would probably let you go to a tea party with her and Valentino. TOUGH! Also, I love Miuccia's designs.
Ooh that's difficult. I think Olivier Theyskens - his gowns are fabulously dramatic, though he'd probably out-pretty me on the red carpet - those beautiful eyes! Or Alberta Ferretti - she'd be fascinating company and her gown would make me feel like an ethereal fairy queen!