Black tea is the the most common type of tea we are used to here in the West. Over all other types of tea black tea maintains its taste the longest, several year in fact, compared to just a few months for the less oxidised brands like green and white tea. Classically this made it the perfect tea to trade and still to this day accounts for 90% of the international tea trade.
It has become common to add milk to many types of black tea. However the proteins in milk block the antioxidants that are present in the tea preventing them from being used by the body. For the maximum benefit from this refreshing drink keep it black, and sweeten with a little honey.