You can do something with CSS if you want (though you have to add/remove categories manually, but how much do you add/remove favorites anyway):
@namespace url(http://www.w3.org/1999/xhtml);
@-moz-document url-prefix("http://www.dslreports.com/forums")
{
a.fcatt[href="/forums/55"], /* Technical */
a.fcatt[href="/forums/57"], /* DSLReports.com */
a.fcatt[href="/forums/59"], /* Voice Over IP - VOIP */
a.fcatt[href="/forums/62"] /* Security */
{ color: gold !important; /* or any color you like */
}
}
Looks like this:
Fav forum categories w/gold text
You could do something else than just change the text color, but I'm not sure how useful it is to begin with... but here it is if you want to play with it. :D