Naomi Novik: Temeraire (a series of eight or ten books or so). Napoleonic war with dragons. The dragons are sentient, but treated as something between slaves and valued servants, so in addition to war drama there's a lot of plot around human rights for dragons
Just a follow up- I read the first one and thought it was fare, but probably will continue looking for another series. Oh, and yes, I saw the "right of the worker/servant" theme built into it but didn't find it to be dealt with in such frequency that it became obnoxious.