The Drowned Cities because I loved The Windup Girl. The future that Bacigalupi creates makes utter sense within the context of global climate change. I've never felt, when reading science fiction, such a sense that I was reading something very akin to what our future would be like. I loved The Windup Girl in part for the same reason I love The Drowned Cities: the made girl, and the half-man, are human-created artifacts that might actually survive our deep human foolishness. We are shortsighted and emotional and do stupid shit, but humans adapt, and we also create tech that adapts--a dubious gift, but a gift nonetheless.
The coywolv, a species existing in the spec-fic future of The Drowned Cities, is potentially happening just now. Just as a similar landscape is taking place.
I'm basically saying read all his stuff because he gets what the future looks like because I really think he is looking at the world we live in right now. And his vision of the future should give you all the pause you ever wanted.