In some deck design situations you may feel that it is important to block certain views to increase privacy.  This can usually be achieved by building a privacy wall or fence.  There are many conventional privacy wall or fence designs for these structures (check them out Decks.com photo search).  You can use this as a great opportunity to express some style and an attention to detail into your design.  Some privacy walls incorporate an arbor feature across the top.  Fence boards, lattice, and even metal balusters are common material choices for privacy wall or fence construction.  Remember that privacy walls and fences are still enforced as guardrails and must beet all code requirements.