The first thing that comes to mind is a bird. When I look up at the sky, I am always enamered by their beauty and effortless grace in the sky, their freedom, and I think I would enjoy being one rather than any other animal because of how easy it seems to be, escaping from predators. More specifically, I think I would want to be an Eagle of some sort. Eagles are predated by very few things, and always appear so majestic and powerful as they soar on those mighty wings.
I have to say monkey! They are so entertaining and look to be so care free, swinging on the branches, climbing to new heights. They are very loving and nuturing just like us and they love banana's, I could live off banana's.