Most watches are derivative in their design which is not bad. It is that a beautiful watch to me is the first design from which most of the rest draw their style points. So I choose the first Rolex Sub as one of the most beautiful dive watches. I appreciate the simplicity of the design most as form does really follow function.
A beautiful derivative design is the Marathon SAR - I'll let the photo say it all on this one.
Finally, the Omega Planet Ocean is captivating in the way a stunningly beautiful woman is, people are drawn to look when I wear mine.
Disclaimer: These photos were not taken by me.