Tuscan. Because of it's simplicity, the Tuscan order is seen as similar to the Greek Doric order, although its proportions follow the ratio of the Ionic order more closely. As defined by the Italian architect, Sebastiano Serlio, the Tuscan order was suitable for fortified places like city gates, fortresses, castles or where artillery was held. In more recent days in a residential application, it became a part of the Georgian style due to the ability of carpenters to easily work up with a few planing tools.
Craftsman. Otherwise known as a square column, the craftsman column is typically tapered and is most often seen as a defining characteristic of Arts and Crafts homes. They are handsome, historical and simple in style. Tapered square column can be combined with supporting pedestals constructed of other materials like stone, brick, stucco or even wood siding.
Stone. These columns ad a natural element to the exterior of a home. Stone can create a more rustic appeal or ad a level of sophistication with an almost castle-like appearance. Even contemporary styles can incorporate this type of column.
Sources:
http://en.wikipedia.org/wiki/Tuscan_order
http://www.houzz.com/ideabooks/1834504/list/Renovation-Detail--The-Tapered-Craftsman-Column