Holy Grail of Fountain Pens

[calamus]

I went to see a doctor recently, and as he took notes I noticed he was doing it with a very attractive fountain pen. I asked him what it was, and he replied, "Oh, it's a fountain pen." He enunciated "fountain pen" very carefully, in case I was unfamiliar with the term. So after I explained to him that I owned several fountain pens myself, but didn't recognize his, he replied that it was a Visconti. We had a jolly chat about pens and inks (he mixes his own from two different Diamine colors), and in the course of the conversation he mentioned that the Visconti was his "Holy Grail" of pens. That started me thinking about the whole concept of a Holy Grail of pens, and what that would mean to me. What was my Holy Grail of fountain pens? And specifically, what was I looking for in a pen that would make it the perfect pen for me? Not so much a matter of am I looking for a vintage Waterman wet noodle or a Meisterstuck 149 or a Sailor KOP or a 1909 S VDB with a fringe on top, but more what characteristics am I looking for? What is it that makes that Visconti or that Pelikan or that Parker or that Conway Stewart just what I've been looking for? And then I thought it would be interesting to hear other people's takes on the subject, and therefore this thread.