Leviathan - Scott Westerfeld

This alternate history novel takes place during the first world war. You know, the one that started when an Austrian archduke called Franz Ferdinand was killed, followed by the biggest freak-out over an assassination that the world had ever known.
In this particular alternate history novel, the archduke has a son, Alek, who escapes after his parents' assassination with a few loyal people in a Stormwalker. A Stormwalker is a specific model of machine, fitted with cannons and guns, that walks. I imagine it as a non-intelligent robot, and it is one of the many constructs the Clanker alliance uses. Because, by the way, Germany, Austria-Hungary, and the Ottoman empire are all allied, and they are very partial to mechanical technology.
The other side in the war, the Darwinists (Includes Britain, France, Serbia, Russia, etc), are more partial to genetically modified technology. Yes, Darwin managed to discover DNA, and to find ways to design creatures by genetically modifying them. One such creature is a HUGE modified whale called Leviathan with hydrogen bladders, symbiotic hydrogen-emitting bees, and a plethora of other species on which its survival depends. This modified whale is the biological response to the Clanker zeppelins, and it is used for essentially the same functions.
Okay, I'll stop now or else I'd be summarizing the whole story. Let's just say that it was a fun, easy read, with nice illustrations, kickass cover art, and that I'm looking forward to the sequel. It's steampunk that doesn't fall into the tired clichés of the genre.