Many people ask me that question!
My eternal favorites are "Philosykos" by Diptyque and "2" for men by Comme des Garçons.
"Philosykos" is for men and women and is so much lighter and more feminine than "2", so I usually switch between both of them whenever I feel like it.
In all these years I've never found better perfumes than these two!
What is your signature smell?