Santiago, the capital of Chile, is a beautiful city where I stopped for a few days on my way north to San Pedro de Atacama. I took it pretty easy while I was here and I stayed in barrio Belavista which was nice and central with good transport and close to cafes, restaurants and the nightlife.
While in Santiago I spent one afternoon walking up Cerro San Cristobal to be treated to fantastic views over the city and out onto the Andes in the east. If the trail looks a bit steep you can also take the gondola up to the top. The other thing that I would recommend that I did while I was there is to take the walking tours offered by Tours 4 Tips. They have two different tours, one in the morning and one in the afternoon. They are different and both worthwhile. The cemetery that you visit at the end of the morning tour is quite amazing and the history and culture that you learn along the way on both tours is very informative.
After Santiago it was another long, but scenic, bus ride up along the coast and then inland to the high dessert town of San Pedro de Atacama.