I want to add an electrical outlet in my unfinished basement. It makes sense to run the wire along the ceiling because that's where all the other wires are. What is the proper way to install NM cable either parallel to or perpendicular to the ceiling joists, given that the ceiling is not insulated and the joists are exposed?

The current situation is a bit mixed. Parallel wires are sometimes stapled to the edge of the joist and sometimes to the side, but not generally as far as 19 mm (3/4 in) from the edge. Perpendicular wires are mostly stapled to each joist and hanging freely between, but sometimes stapled to a board.

I live in Massachusetts, and therefore are subject to NEC 2008 with amendments.