For marking on light fabrics, I use the Ultimate marking pencil, which also has refills available, in the usual pencil lead, or colors. For dark fabrics, I love the Fons and Porter white marking pencil, which also has refills in colors. Both of these pencils make very fine lines, include erasers, which actually work, and I find that I need no other marking tools.
Fons and Porter can be found at JoAnn's or quilt shops; I have only seen the Ultimate Pencil at quilt shops.