When it comes keyboards, there are two major kinds: mechanical and membrane. Membrane keyboars are cheaper to produce and less noisy, which many think is convenient for things like office work. However, most of all gaming keyboards are mechanical with Cherry MX keys. Most gamers prefer mechanical switches, since they provide a steady resistance and return to their default mode faster after a key is pushed. Mechanical keyboards can also handle approx. 50 million keystrokes, while membrane keyboards can handle approx. 5 million keystrokes. Recently, there have also been a number of hybrid keyboards in different variants - these basically have the same advantages and disadvantages as mechanical keyboards, but manage to keep a slightly lower noise level due to the different design.
Macro keys are programmable special keys players use for mapping / programming various functions. If you want to change the look of your mechanical keyboard, you can buy cool and colorful keycaps. Many also appreciate a gaming keyboard with backlight, especially if the keyboard is often used in a dark room.