Mine is Issey Miyake L'Eau d'Issey. Introduced in 1992 L'Eau d'Issey (Issey's water) is a light, fresh, water floral with hints of lotus, cyclamen, freesia, and white lilies. The base notes are sandalwood, moss and cedar which keep the fragrance from being too feminine and sweet. The bottle, designed by Miyake himself, is based on the view of the moon behind the Eiffel Tower from his Paris apartment. I occasionally wear his men's fragrance L'Eau d'Issey Pour Homme when I'm wearing a tie.
I adore Robert Piguet's Fracas, Hanae Mori Magical Moon is divine and one of the best presents I ever received was a bottle of Chanel No. 5 on my 40th birthday along with a note that said "you're finally old enough to wear this". But my go to bottle will always be Issey Miyake. What's your signature scent?