Wonks and the Nerd Taxonomy

Heard the word "wonk" used on the radio this morning and it started me thinking.  "Wonk" is used to refer to policy nerds.  But, of course, there are quite distinct nerd populations, some of which are even in perpetual conflict (Hat tip to Nick for this one)  Do we have other terms that are discipline-specific nerd markers?  If not, for what groups ought we have them and what would be possible options?