I personally like the summer version of YSL Opium pour Homme. I know in previous years it has been called Opium pour Homme Eau d'Orient, but I think I read that his year's version is called Opium pour Homme Eau d'Orient Poésie de Chine.
I am a big fan of the original Opium pour Homme, but it is way too heavy of an oriental scent to wear in the summer. The Eau d'Orient version is a lighter/fresher/modern take on the original with the introduction of notes such as grapefruit and vetiver. Plus I think it has pretty gone longevity for a summer scent.