If you want something else, go to Admin Panel -> Themes -> Toplist Generator. Select to make a toplit of categories ordered by priority ascending. in the advanced filtering condition field, enter
parent=0
to tell it to only include the top level categories. For the toplist content you could use <li<IF {CATID} is {THISCATID}> class="currentcategory"</IF>> <a href="{CATURL}">{CATNAME}</a></li>
and then wrap the whole toplist output it gives you in <ul>...</ul>. Copy and paste to wherever you want the list of top level categories displayed.