Depends on how clear the subcategory headers are, I think - it should be obvious at first glance what's behind the link for easy navigation, so while a simple and obvious literary allusion along the lines of "Here be drama" for the drama category might be fun, using a quote from a Shakespeare drama or something like that would just make things confusing.
Basically, don't make navigation a guessing game. ;)
Re: Vote for Archive of our own + thoughts on sub-headings
Basically, don't make navigation a guessing game. ;)