a problem when you have a navigation list with an link that needs to be centred in the box/li. normally setting the lineheight to the height of the li does it. but if you have a link with text that wraps then it gets difficult to vertically http://www.mindanews.com/buy-topamax/ centre the words.
thanks to this CSS tricks i found a way.
make the li position:relative; (it already was) and change the li a from display:block to display:table-cell; and add text-align:center;vertical-align: middle;.
Seems to work. Have not tried in all browsers yet but ok in OPera and firefox, so, hopeful.