If the natural look and appeal of wood is top-on your deck design list, then use cedar. The heartwood of the tree (the deeper colored red-section, not the white sap-part) is highly rot resistant. Since it lies flat and straight, it is super-easy to fit in place. In addition, this sturdy and structurally solid wood can be surprisingly light. There are basically 4 best grades of cedar that can be used for decking including: custom knotty, architect knotty, custom clear, and architect clear. Moreover, the cost of cedar wood is moderate, somewhat less than materials such as exotic hardwoods.