All three Starwoods are great, each an outstanding value in its respective category, with helpful and friendly staff. Santiago is also full of suite hotels (called apart hotels) there are cheap and quite practical (with breakfast and self catering facilities). I like the La Fayette, which is about US$70 per day and provides free transport from the airport. You can see it on the internet:

http://www.chile-hotels.com/lafayett.htm