You have two general options when choosing decking materials for your home: wood materials and composite materials. Wood is the most commonly used of all decking materials because it is generally easy to work with and is inexpensive when compared to some other types of materials. Composite materials are relatively new additions to the market, and they often combine wood fibers with plastics and other synthetic materials. Sometimes the boards can be made exclusively with these synthetic materials, eschewing wood to avoid decay or rot. A third and far less common option is aluminum.
Aluminum decking materials are very strong — in most cases, several times stronger than wood and composites — and it actually dissipates heat very easily, meaning the deck will stay cool during hot weather. The aluminum will not rot or rust, and bug infestations are extremely unlikely. This material is not often used, however, because it can be cost-prohibitive. It is usually far more expensive than wood or composites, and while it is often easy to cut and work with on-site, it is not always the most attractive option.
Several types of wood can be used for decking materials as well. Pressure treated lumber is wood that is chemically treated to resist rot, bug infestations, cracking, splitting, and warping. This wood is likely to last a long time, but it is also likely that the wood will need to be re-treated periodically to ensure the wood will remain strong and resistant to damage. It can be quite pricey as far as woods go, and it will usually need to be painted or stained, as the chemical treatment often makes the wood appear green and not especially visually appealing.
Other woods such as cedar are just as resistant to weather damage and bug infestations as pressure treated lumber, but few or no chemicals are needed to accomplish this. Cedar is also exceptionally beautiful, so many deck owners will choose this material not only for durability and function, but also for visual appeal. Teak will feature many of the same properties and visual appeal, though it can be quite expensive.
Composite materials tend to last an exceptionally long time, and while they may not have exactly the same visual appeal as wood, they are far less likely to rot, warp, crack, split, or wear out quickly. The downside to composites is the susceptibility to mold and mildew, though the materials will require little maintenance overall. Composites may also be slightly more difficult to install on-site.