Spinning tops are, to me, a perfect example of "form follows function", the theory that an object's design should be based entirely upon what it is intended to do. When done correctly, they are are beautiful in their essential efficiency. Spinning tops are, to me, an elegant example of this concept. They are beautiful when standing still and even more so when in motion. Watching a top silently spin, its colors blurring and blending can create an almost hypnotic moment.
Here are some designs that I found to be particularly beautiful: