There's the map. We are in south Providencia, an area almost completely made up of apartment buildings. It is on the wealthier side of town, with minimal trash, lots of trees and very green grass in the few places that it is. It has a very active local government, with many employees watering grass, picking up trash, etc. In the north of Providencia is the area known as "Sanhattan" (Santiago+Manhattan) and is full of big corporate buildings, people, and more people. Also in this area is the Costanera tower. In the north-west side of Providencia is the Cerro (hill) San Cristobal, which is a public area, uninhabited with gardens, restaurants, etc. and makes up about a quarter of Providencia.
Over the cerro is Recoleta. This area, from what I have seen in the south side, is business based, many small shops all with garage door fronts, for security. It is LOADED with graffiti and trash. Literally, big piles of trash, un-bagged sitting on the side of the road, and a huge piece of graffiti art on 99% of the store fronts. North Recoleta is where La Vega, the big food market is. There is a large, fairly nice sector, that is very busy during the day, with lots of women shopping for mostly cheap, imported clothing, shoes, jewelry, etc.
South of us is Nunoa, (pronounced "nyoonyoah") which is similar to Providencia, but with smaller buildings and a little more trash, more houses, simply a result of an area with less money.
Las Condes is the biggest and most spoken-of comuna. It is not as big as it looks, with the east 30% of it being mountains. It's like a bigger, more wealthy and more spacious Providencia, with houses instead of apartment buildings. This area is not as bicycle-friendly, and it's more like the US.
Vitacura is very similar to Las Condes.
Lo Barnechea (official name) everyone calls it "La Dehesa". This area is the nicest area in all of Santiago, with Absolutely NO trash, lots of high-end car dealerships, and big houses in gated neighborhoods. It has a level of well-keptness and signs of wealth that I have never seen in the U.S.
Santiago Centro is the official, government center of the city. It is packed with people all times of day, has no grass or trees except in parks, and is a combination of business and residential buildings. It is the oldest part of town, and the center of petty crime like pickpocketing, because of the constant mass of people.
La Reina, Penalolen. These are more undeveloped, poorer areas. Out here, property costs vastly less than it does in the comunas north of it, so you will occasionally see a huge mall or supermarket, simply because they had the space to do it.
La Pintana and Puente Alto are considered the bad side of town. I have never been to either of these.
The rest of the comunas I do not know enough about to be worth describing.