The best baba ganoush I've ever had, by far, is at the Lebanese Butcher in Falls Church. They've recently reopened after a fire, and I don't know if the restaurant has reopened yet, but the baba ganoush is available for takeout in the grocery (along with very good hummus and tabouli).
Lebanese Butcher & Restaurant
109 E Annandale Rd, Falls Church, VA 22046
My favorite style is without tahini. Very few places carry the Sabra brand (you can easily find fifteen kinds of Sabra hummus, but no baba ganouj). I know it is at Wegman's in Fairfax and certain other stores. Balducci's does their own version like this.
In a restaurant, I would say that Me Jana in Arlington is top flight. For a strong flavor made chocolatey brown from smoked paprika, go for the version at Mazadar Kabob in Fairfax. They get extra credit for having great breads.
2300 Wilson Blvd., Suite 140, Arlington, VA 22201
600 Franklin St, Alexandria, VA 22314