For advice on CSS we need a link to your site, unless you are using the vbulletin default template structure. All I can offer is a starting point, which may or may not work with your style.
The following code will adjust the height of the line or the lines margin and its associated container. You will have to alter the actual values to your style.
Code:
.navbar {
height: 62px; /* container size */
}
.navbar ul {
line-height: 40px; /* this may work for you */
}
or
.navbar ul {
margin-top: 10px; /* or this may work for you */
}
[/code]