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 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.