How can I use CSS to vertically center the text in an anchor, within a LI?

Old question, but the answer can now be updated with Flexbox.

a {
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
}

You could use display:table, etc. along with vertical-align:middle

ul.c {
    text-align:center;
    display:table;
}

ul li {   
    float:left;    
}

ul li a {
    text-decoration:none;
    border: 1px solid Maroon;
    padding:2px 12px;
    background:#FFEF8A;
    width:100px;
    height:52px;
    display:table-cell;
    vertical-align:middle;
}

ul li a:hover {
    background: #CCC;
}

Example: http://jsfiddle.net/kf52n/2/