Rollerball pens are my preference. Usually with a Pilot G2 refill, if one will fit. My current daily drivers are (in order of current preference)
Honestly, all these pens are just window dressing for the superb Pilot G2 refill that most of them use. You can get the same writing quality from a two dollar Pilot disposable pen. But as Nietzsche said in reply to a friend who said his typewriter had changed his manner of writing, ‘You are right, our writing equipment takes part in the forming of our thoughts.’
Fountain pens are like driving a Model T on the interstate. The ink smears while taking notes, they skip and dry out quickly so they don’t start properly when trying to take notes, etc. They also shade, and I don’t care for that. I’ve tried Noodler’s and Monte Blanc inks with a Monteverde pen I had (gave away), and the best I’ve used to date is a Pilot Varsity disposable. It writes well and doesn’t exhibit the problems mentioned. It mainly lives in my pen box.
As for paper, Rhodia/Clairfontaine seem to be the best for me. I like the No 18 3-hole notepad, their WebNotebooks are nice too. Leuchtturm 1917 is second probably. Moleskin is too rough, and isn’t to my liking.
I finally broke down and tried Tomoe River since everyone raves about it. It’s too thin for my taste, and ink shows through so only one side of the sheet is usable.