this is very subjective and there are very few, if at all, people who can name only one. There are many scents in the market, designers and niche that I like and I can't really say that there is one ultimate. Of course, some are better than others and most ppl may generally agree that Cool Water can't compete with Chanel Antaeus for instance, or Azzaro PH etc.
There are those that are trying to find holy grail of scent, but when and IF ever found, it is a holy grail to them only.
From scientific, chemist aspect - mayhaps there is the best one existing, and such contains perfect ingredients in best proportion or ratio.
I myself enjoy a lot of fragrances and adore vareity, so I don't care if there is one best ever made. Mayhaps there is and was worn by Egyptian Pharaoh 2500 B.C., or maybe Babylonian kings. Ancient peoples loved perfumes and perfumery is very old craft. We'd be surprised what creations ppl made in those ancient times! That is what I would like to find out and smell