I'd add Occidental Grille (very DC) and one of my faves is Vidalia. I just went to Thai Square for the first time recently. It was the best Thai I've had outside of Bangkok. It is in Arlington on Coumbia Pike near Glebe. No metro and too far to walk from the westin, but perhaps you could stop on the way to the airport. If you are going early, I doubt it would be very crowded and I'd bet they would find a place to store your bags if you took a cab.