Ethiopia
Coffee, or rather the coffee plant coffea arabica that is the source of all specialty coffees today, is native to what is now Ethiopia. Wild and semi-wild stands of trees are still tended there by small farmers. Ethiopian coffee has always been a favorite of mine; I think it's what coffee is supposed to taste like, possibly a result of the genetic diversity still found in this native species -- just my theory anyway. There are many great coffee regions of Ethiopia -- Djimmah, Limmu, Ghimbi, Harar, Lekempti, Sidamo, and Yirgacheffe (the names are usually the growing region, though sometimes a nearby city, or even the local people).
Although all these coffees share some taste characteristics, they can be as varied as the spellings and pronunciations. One large difference is whether the coffee is wet processed (called washed, Yirgacheffe and some Sidamo, for example) or dry processed (called natural, some Sidamo, all Harar). Our Harar is from the eastern highlands near the city of the same name, grown at altitudes of up to 3000 meters. It tends to have great acidity, full body, and at its best, a pronounced fruity flavor and aroma found in no other coffee. I think of Ethiopians as fruity and wild, while Kenyas are winey and floral.
Because of the simple growing methods used in Harar, it's a naturally organic product. The one problem with Harar is that because it comes from many small farms, the coffee is often inconsistent, even within the same lot (the bags are marked with a lot number). Even cupping each lot before you buy doesn't guarantee you know what you're getting.
Kauai
Coffee is grown in the United States only in Hawaii (at least if you don't count Puerto Rico), and while the best known -- and most expensive -- is from the Kona coast of the Big Island, there are commercial farms on Maui, Molokai, and Kauai. I first tasted Kauai in the early 90's, and frankly it was almost undrinkable, but the 3500 acre estate has made great strides in growing and production and now our Kauai Estate Hawaiian is one of our best sellers.
Kauai, because it's grown at a low altitude, shares the low to medium acidity of other Pacific rim coffees. This can be an advantage when roasted to a medium dark brown. This roast increases the body and enhances it's distinctive flavor when drip-brewed, and makes a very smooth, light espresso.
Kenya
Coffee from Kenya is some of the most distinctive -- and distinguishable -- in the world. Once you know what a Kenya tastes like, it's easy to tell one from middle-of-the-road Centrals or mellow Indonesians. Kenyas are highly acidic, full bodied, and have a bright, floral taste. That taste is often called "winey" -- that's a compliment -- and Kenyas are sometimes compared to wines from Bordeaux. Kenyas are a washed or wet-processed coffee so there is less of the rough or earthy taste of natural Ethiopians.
The "AA" part (usually spoken as "double A") indicates the bean size; most Kenya imported into the US is the largest AA grade, though occasionally you'll see a slightly smaller AB. The Kenyan government gathers up all the country's coffee and sells it at auction, a method which has managed to keep Kenya prices high while the rest of the market has slumped to historic lows. The principal growing regions of Kenya are in the south western mountains near the capital Nairobi. Most of the Kenyas we get are from small estates with unpronounceable names, though an estate origin is by itself not a guarantee of quality.
Sumatra
Indonesia is the third part of my triumvirate of coffee. The coffees of Indonesia, including Sumatra, Celebes (now called Sulawesi), Java, Timor, and Papua New Guinea (an independent state) share characteristics of full-body and medium acidity. I think of a Sumatra as the opposite of an Ethiopian or Kenya. Sumatras are prized for being mellow and having a desirable earthy taste not found in any other coffee. It doesn't have the clean, sharp taste of a Central, or the winey finish of an African.
The term Mandheling is the name of a tribe and is not strictly a growing region. The same thing is true of Gayoland, but that area is in the northern province of Aceh. This coffee is certified by SKAL, though of course we can't put that on the label because we're not certified by USDA. I know this is Asheville, but Gayoland is pronounced g-eye-oh-land, not gay-oh-land.