There are three main breeds of turkey, all of which have a slightly different flavour...

White
White turkeys generally have larger wide breasts and short stubby legs and are considered more flighty than their Bronze cousin.
Some people prefer White turkeys due to the appearance of their clean-looking skin and subtle flavour.
Black
The Norfolk Black became the favoured eating bird in Britain and in the 1700s large flocks of birds were driven to London with their feet tarred and clothed to prevent damage on the long walk.
Black turkey characteristics include a fuller, gamier flavour, a smaller breast than the White varieties and a fine texture.
Bronze
Named for its unusual colour, the feathers of this breed are a shimmering green-bronze, often appearing metallic in sunlight.
Bronze turkeys tend to be more traditionally reared and are usually free range. Like their Black cousins, they are famed for a distinctive gamey flavour and moist meat, but also have a firm texture.