I'm an artist who makes math and physics visualization sculptures, I LOVE taking notes on 18"x24" drawing paper with a combination of colored pencil, fountain pen, and gel pen. For long derivations rather than notes/sketches, I prefer 11"x14" drawing paper in two columns because I think it's more comfortable to work with, but it still gives me that bird's-eye view of everything I want if I go back and color code stuff. A lot of my work is done in regular size sketchbooks, though.