Philip,
That is a wonderful photo, and Saunton's first definitely seems a contender for the title.
I'm partial to Machrihanish. In terms of aesthetics, Royal Aberdeen should be in the running as well, as it's opening tee shot has such a strong sense of invitation to the seaside site spread before you. But, whereas RA's first takes you down to the sea, Mach places the golfer next to the sea for the first stroke. This, coupled with the classic strategic question it poses, makes it the best opener for me.
Ken