Is "www" desirable in web site URL?

[John Kupersmith]

I'm helping construct the URL for a new web site.
It will either be:
     http://www.co.washoe.nv.us
or:
     http://co.washoe.nv.us

Does anyone know of any advantages or disadvantages of having
the letters "www" as part of a URL ... aside from saving key-
strokes if we leave it out?  (BTW, this site doesn't exist yet, 
so no point in trying to access it!)
--jk
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  John Kupersmith                          jkup at washoe.lib.nv.us
  Internet Services Librarian        http://www.washoe.lib.nv.us
  Washoe County Library                     voice:  702-785-4137
  301 South Center St., Reno, NV 89501        fax:  702-785-4609
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