Here is what I've been using to fill in my eyebrows:
Maybelline Natural Smokes quad & Marcelle Accent Eyebrow Crayon in Charcoal (from Canada)
Right now I'm using the pencil because it's much more softer than using the eyeshadow in the quad. Since it's from Canada, I wanted to find other alternatives, so I picked up NYC's Brow/Eyeliner Pencil in Charcoal and Taupe from CVS.
Top to bottom: Maybelline quad, Marcelle pencil, NYC Charcoal pencil, NYC Taupe pencil
I thought that both the NYC and Marcelle pencils would be similar, but the NYC one is really dark as you can see above. The NYC pencils are really nice in that they're only 99 cents and very waxy.