I would choose something with a single bulb, with the fixture centered over the mirror, rather than a long bar with multiple bulbs. Also something that extends a small way on a metal arm (curved) rather than flush with the wall. Like this, mounted with the bulb facing down:

http://www.lampsplus.com/products/chrome-and-cased-opal-glass-9-inch-high-wall-sconce__j1187.html

We are redoing a powder room and have this mirror over a pedestal sink: http://m.lampsplus.com/products/cooper-classics-lawson-white-26-inch-x-37-inch-wall-mirror__x1775.html. Any ideas on lighting options that would complement and not conflict? Thanks!