If you want all the cells in the table affected you can cut down on the html doing something like this
table#mainNav {}
table#mainNav td {
background-image: url(images/navBG.jpg);
background-position: top left;
background-repeat: repeat-x;
border-right: 1px solid White;
}
table#mainNav td.last {
border: 0px;
}
table#mainNav td a {
font-family: Arial;
font-size: 12px;
color: #FFFFFF;
font-weight: bold;
text-decoration: none;
}
table#mainNav td a:hover, a.selected {
color: #FBB040;
}
Then just id the table and add the class for last and selected
likewise if it is just that 1 row, you can single it out by id'ing the table and give the row a class
table#mainNav tr.navClass td {
background-image: url(images/navBG.jpg);
background-position: top left;
background-repeat: repeat-x;
border-right: 1px solid White;
}