The most common building in GRA. They are of all sorts, from small houses to large mansions with several floors. They can be good looting places for new players as containers (chests, shelves..) are rarely locked and even more rarely with alarm systems. However, NPC tend to lock their doors before leaving.
There's all kind of shops around the city, from groceries to weapon stores. This is where you can buy or sell (pawnshops) most of the stuff you want or don't. Most shops (except weapon shops) have a high skill safe. If you manage to break into those safes, you'll be able to loot the shop.
Factories are usually large buildings. This is where raw materials are converted into goods that can be sold by stores. They also have a safe that can be looted for goods. However this is a dangerous task as factory workers will probably detect you.
This is where you can be healed and where you can buy medicines. Sleeping in a hospital bed will cost you money, but it will also restore your health. Like factories and shops, there's also a safe to crack with all the available medicines to loot.
In those locations, bumping into a table (or using it) will provide you with food in exchange for some money. In some of those buildings you'll also be allowed to purchase food directly. Those buildings tend to be relatively busy.
A fairly uninteresting building. This is the workplace of roughly 1/3rd of the population.
This is where NPC are putting their money. This is typically a several floor building with high security vaults containing money. Banks will be guarded by security guards and will be hard place to break in.
They usually have a graffiti next to the door. Those buildings are criminal organizations' HQ and you may not always be in there. However, this is where you'll find valuable, illegal, weapons and drugs.
In the current 0.6.7 (as I'm writing) version there's only one of them, however, Gang Hideouts and other buildings may be morphed into dungeons in a later version. Dungeons are typically large buildings with several floors. They feature loot, new/unique enemies and usually a boss and/or a special reward.