I assume when you come on Hacker News you feel offended for being called a hack and a criminal :P.
Colloquial usage of these terms has shifted massively, to the point where the most common definitions I hear from people are:
nerd: someone with an obsessive interest in certain intellectual areas, especially academic/technological things (math/computers/the sciences/etc.)
geek: someone with an obsessive interest in certain subsets of popular culture, especially ones relating to fiction (games/comics/novels/etc.)