Black peppercorns come in many varieties with varying degrees of heat and flavor complexity. The largest black peppercorn is the Tellicherry, considered to be the best because it's left on the vine longer for more developed flavor. Other black peppercorns are Sarawak, Malabar, and Vietnamese, but unless you're buying from a specialty spice store, the packaging usually doesn't specify the origin.
Try to buy peppercorns from a source with good turnover.
Like most spices, black pepper tastes best when freshly ground. A quality peppermill allows you to control the size of the grind from fine to coarse. For cracked and very coarsely ground pepper, it's good to have a mortar and pestle on hand. And for grinding large quantities, an electric spice grinder or coffee mill is a real time saver.
Store them away from heat and light (like any spice), and use them within a year.