It seems that the more "popular" drives are to the viņas - you can also arrange for day tours (which I have yet to do). It is also a very nice drive out to the coast (Viņa del Mar / Valparaiso). Although I was nervous about it in advance, it was a pleasant drive on a very nice ruta (con peaje). I wouldn't recommend driving in Santiago (I rented the car at SCL and drove right to the coast), although Santiago driving appears easy compared to much of Europe or Latin America. And if you need a quick lesson en "espaņol chileno" - just make sure that you don't drink too much "schopp" with your "ave palta" or the "carabineros" will pull you over as you drive on "Calle 2 poniente".
Disfrutelo mucho - I'm hoping a return to Chile late this year.