Hunter,
Here in the Boston area the most common varieties of Domino Sugar are Confectioner's (10X) and Superfine (both in one pound boxes), and Granulated (coarser/bigger crystals), in various sizes, but most commonly seen in one, five or ten pound bags and, I think (have never bought it), four pound plastic canisters.
The sugar that you see around here in sugar bowls and dispensers, particularly in coffee shops etc is more often than not the Granulated, which is also used for cooking/baking. Every once in a while you see people who do use the Granulated for baking/cooking, but will serve Superfine in the sugar bowls for sweetening coffee/tea etc at the table; sometimes a recipe or two will ask for superfine or confectioner's sugar too.
I'm told, but have never seen it, that there's also a grade of sugar for sale called Confectioner's (4X) which is not as finely ground as the 10X which is commonly sold in the supermarkets and used for icings etc.
Hope that helps,
-- Paulo.