I have a Mont Blanc presentation pen, inherited from Dad, that I use for real letters and I fill it from a bottle of ink from the Mont Blanc company.
I use ball point, roller balls et.al. for notes and other stuff and indelible markers where needed - like addressing packages, marking lower hems on linen with purchase date, and their clothes when boys were young and went on ski trips.
I also use China markers for glass and plastic and on glossy photos to ID them (you know the crayon-like markers that have a string so you can unravel the covering to expose more marker.)
When I was a reporter I was always searching for good pens that did not "drag" on the paper and allow for fast note taking!I love using Dad's Mont Blanc pen... it writes beautifully and I seem to think more about what I am writing and proceed as a slower pace than I do when jotting a note.

Here's a handy device someone told me about years ago : if someone asks to borrow a pen -- and you need it back -- hold on to the cap! It works.
But I would *never lend the Mont Blanc fountain pen - the point is worn just right for my hand.