My goto setup was the Pilot G2 0.38mm pen: https://www.officedepot.com/a/products/527870/Pilot-G-2-Retr...
And the Leuchterm 1917 dotted notebook: https://www.leuchtturm1917.us/notebook-medium-a5-hardcover-2...
The pens have perfect flow, and are thin in stroke for precision work. The paper has a nice texture to it, not rough but not slick.
For quick work, I'd grab sharpies and computer paper, for stuff like quick UI sketches/rapid note taking.
But as of April this year, I've switched to the 2018 iPad and an Apple Pencil and have completely dropped using paper. Being able to find all of my notes on both my ipad and my computer, sketch things up when I'm traveling and send it to my coworkers quickly, and also have all my books and media all in one simple device is just a dream. And in iOS 12, the Notes app is actually pretty great.
It's also a great setup for sketching up ideas to then toss on an Apple TV to share with my team before investing time into making a polished version of something. Idea to presentation in minutes is just awesome.
My only two complaints:
1) the body of the apple pencil is shitty. It's slick and round, I'd prefer a hexagonal body with a textured finger pad and a nice textured surface. This has annoyed me enough to the point that I've actually looked into how to make an alternative barrel for the pencils.
2) I take all of my notes in outline form. I would LOVE an app that captures handwritten notes in outline form, but then adds interactivity like collapsing/handwriting to text conversion/etc while preserving all the format. I realize that's a hard problem to solve, but I'm hoping in a few years machine learning will catch up.