Flautist is of course the usual nomenclature for those of us who, in the immortal words of Monty Python, blow in one end and waggle our fingers up and down - but I do like the American flutist as well.

I've also been referred to as a concertinist, which somehow seems to work better than concertinaist. Personally I tend to refer to myself as a 'flute player' and a 'concertina player' - and with my third and fourth hats on, neither 'low whistler' nor 'low whistlist' seem right, whilst rauschpfeifer is perfect ...