I found a cool trick on Wikia for superheroes (or optionally anybody) to use to highlight their usernames.
Simply copy this into the wiki's MediaWiki:Wikia.css
a[href$="/wiki/User:Admin's_Username"] {
color: #006600 !important;
font-weight: bold !important;
font-family: Arial !important;
}
Replace "Admin's Username" with your username.
Optionally, you can also change the color for the Message Wall, User blog, and Contributions links, in addition to the user's name, with this:
a[href$=":Admin's_Username"],
a[href$="/Admin's_Username"] {
color: #006600 !important;
font-weight: bold !important;
font-family: Arial !important;
}
Credits to: http://dev.wikia.com/wiki/Admins_%26_Bureaucrats_Highlight