A naturalist. Preferably on a project to study wolves by living among them.
Also a ballerina. I have been told I have a natural "pointe" but I seem to have missed that calling..
Besides being a sailor I always wanted to be a gangster and wear a black suit like dudes do in Reservoir Dogs.
Being a writer, a musician or an artist comes close..
I want to be a zillionaire, so I don´t have to have a job and just relax. And after I am relaxed enough, I will try whataver I like: being a priest, being a musician, being a painter, being a fashion designer, cosmetic producer and make-up artist, movie maker, director... whatever
You mentioned my favorite instrument that I play, and that reminds me that for a few years I wanted to be an audio engineer. Still do, except not so much that I would devote myself to it as a career.