Yes, I love the fact that we get 4 different cow types. Why do we need an entry for "cow" and then a further entry for "Ox", which is a castrated bull (otherwise known as a steer). Then we get the aurochs (wild ancestor of modern cattle), and the rothe (or drow cow). That's something people have clearly been asking for!
Another playable (but flightless) bird race and the goliath reprint are exciting as well.
I remember hearing that orcs and goblins would be statted out as playable races at one point. Guess I was mistaken.
What does excite me is a plethora of critters from the Expedition to the Barrier Peaks module, including the froghemoth and vegepygmy. Maybe the next AP will be based on that old module?