I confess that I like to use high-quality notebooks and writing paper. This morning, I found out that my favorite notebook, the A9, is available online directly from the company that makes it (Rediform)! Not only that, you can get it in four different colors: black, blue, red, and green (I only have blue and black). Why do I like the A9? The paper is fairly heavy-weight and has nice margins for subject, date, and page number. The binding is high quality and the notebook is a smallish size (9 1/4" x 7 1/4"). Finally, the cover is very hard and makes a fine writing surface.
A blue A9 notebook (cover):
Inside the A9 notebook:
A spiral-bound version of the A9 (good for scratch notes):
For filler paper, I use the (expensive) Mead Five Star XL Reinforced College-Ruled, 3-hole punched, 8 1/2" x 11" paper. It is very heavy weight and the holes are reinforced, which I like since I tend to abuse my binders.