I would urge you to consider composites for your fence. It combines the look of wood with the durability of synthetic plastics. Composite fencing material is easily found at any home improvement center. It offers a wide range of colors and there will never be a need to paint or seal it. A composite fence will withstand the elements much longer than even the most expensive wood.
I believe the finest wood types for fencing are cedar and redwood. Cedar wood is known for its durability and natural beauty. Redwood on the other hand has tannic acid that protects the wood from rotting and pest damage. For more details, visit http://www.ehow.com/info_8048408_wood-fences.html.