#navigation li:before {
    content: "|";
 }

#navigation ul.links li,
#navigation ul.menu li,
#navigation a
{

  padding: 0px 5px;
  margin-right: 5px;
  border-radius: 5px 5px 5px 5px;
  float:left;
  color:white;
  vertical-align: middle;
  list-style: none;
  text-decoration: none;
}

FOO:before {
    content: "|";
}
FOO:first-child:before {
    content: "";
}