The material that you choose for your fire pit table is a matter of personal preference. Wood is a good choice for building a fire pit table, especially if you are making it yourself. You can also use stone and mortar in the construction, if you desire a more rustic look. Bricks can be used as well.
Some fire pit tables go a step forward on the decorative front and have tops that are tiled with ceramic tiles. Some tables even feature a tile mosaic top. Whatever material you use is ultimately up to you. Home improvement stores sell the fire pit bowl that will house the actual fire.