One?! There are many makeup items that I wish to own, so here are a few on the top of my wishlist:
Yves Saint Laurent Rouge Volupte Lipsticks

Chanel Pro Lumiere & Mat Lumiere Foundations

TEMPTU AIRbrush Makeup System

DiorSkin AirFlash Spray Foundation 
 
Guerlain Rouge G de Guerlain Jewel Lipstick Compact