Santiago is a amazing city. Althoug some people prefer to stay in Providencia neighbourhood, I choose stay in down town city, in Galerias Santiago Hotel. Althoug busy, Galerias is near everything I would like to see: San Francisco church, a beautiful paleochristian one, Alameda Higgins, Palácio del Gobierno ( La Moneda), peatonales ( Paseo Ahumada) , Archaeological Museum. This Museum worth every minute: You can see the South American History in the mummy, pottery and another articles. Plaza das Armas is near too, and you are lucky, you can see the "Troca da Guarda". Cerro De Santa Lucia provides a fabulous city and Andes vision. You should go to the Market, where there are seafood restaurants, typical from Chile. Try "Ceviche" and drink "Pisco", or the delicious national Wines. Fruits, specially cherry are the best in the worl.
If you like Folkloric Show, Bali Hai has a good show, where you can see the typical dance "Cueca".
If you are alone or not, Santiago is a good choice.