There are many options that can be used for your deck.  Redwood is the old standard, composite decking has many new colors and texture options, and then there are exotic hardwoods.

Redwood Decking: Redwood will be the most affordable, but will require the most maintenance.

Composite Decking: Composites do not require maintenance.  The advantage of the top line composites is their pvc coating that helps them to not fade.  Composites are also installed with hidden fasteners so your deck has a clean look, with no screws showing.

Exotic Hardwoods: Exotic hardwoods are the standard of excellence in decking.  There are many options including Brazilian Redwood, Tigerwood, IPE (pronounced E'pay), and the list goes on.  These natural woods are very durable, beautiful natural coloring, and long lasting.  They have a hardness rating 2-3 times that of oak, which means they will last a long time.  If neglected they are easily restored.  One huge advantage of these natural woods is that they do not absorb heat as easily as composites.