Well, Ill take a shot:

Geek: Usually computer oriented, tends to spend excessive amounts of time on the puter or with schoolwork.

Nerd: Defined by me as one who enjoys fads, then jumps on the bandwagon. Also one who dislikes physical fitness and or athletics.

Dork: This is probably the most negative of the 3 in my opinion. A dork to me is one who dislikes most everything that he/she is not into. A simpleton who judges too quickly.

How was that?

Geek: Someone who is obsessed with something and is really good at it. [i.e. a computer geek].

Nerd: Some kid who's really good at school and other things, and whom some people consider 'weird'.

Dork: Another term for 'weirdo'.

@CzaR: Almost nothing on how I would define them. My point now proven.

@Velox: Interesting...but IDK if exactly to my terms.

So now I understand how I can be called so many different things, lovably, even if I don't think I match.

Though I would agree that dork is the less pleasing of them all.

-CF

Geek: Obsessed with nerdy things, but manageable in a cool way.

Nerd: Smart, sometime with and sometimes without a social life.

Dork: More obsessive, and just plain weird. Willing to blow off real life events for computer/internet events.

I don't really have a good view on them as my school isn't alike to most other schools. Being smart and geeky is really cool here.

EDIT: and we don't really use dork that often. I would say that it is the most degrading though.

Geek: What Velox said. Also a person with an unusual or eccentric personality.

Nerd: An intelligent but single-minded student who is ridiculed as being affected or boringly studious.

Dork: A dull, stupid, fatuous person.

Without thinking it through too much...

Geek: Rather intelligent

Nerd: Socially inept and rather intelligent

Dork: Socially inept

Geek: a person who is proficient in non-social, non-athletic activities; usually involving computers/video games.

Nerd: someone who is smart and usually socially inept.

Dork: a very deragatory form of the previous two (Though I never hear this one used).

A geek is just a nerd who works too hard.

A dork is a not nice thing to call someone... and a fork (which I started to typo) is a utensil you eat with.

©1984-2009 Toaraga EAM

See comment below.

Geek: Starts with a G.

Nerd: Starts with a N.

Dork: Starts with a D.

There's my definition.

Geek: same as nerd, but with an extremely well paying job.

Nerd: the kind of person you'd expect to speak Klingon, or have created a 1:50 scale model of the Death Stat in their backyard.

Dork: a short term cool dude

~ :e:

Geek: A nerd who is also good with technology.

Nerd: Someone (usually introverted) with a specific (I don't want to say obsession, but that's what it is) about something. There can be anime nerds, internet nerds, sports nerds, video game nerds. Any sort of hobby, activity or past time can have a nerd following.

Dork: A nerd who's obsession is so, for lack of a better word, intense. That it alienates other people.

Super Nerd: Fools who only use magnimites, voltorbs and grimers.

Geek: same as nerd, but with an extremely well paying job.

 

Nerd: the kind of person you'd expect to speak Klingon, or have created a 1:50 scale model of the Death Stat in their backyard.

 

~ :e:

Geek: A nerd who is also good with technology.

 

Nerd: Someone (usually introverted) with a specific (I don't want to say obsession, but that's what it is) about something. There can be anime nerds, internet nerds, sports nerds, video game nerds. Any sort of hobby, activity or past time can have a nerd following.

Y'see, here's where things are really going awry in my head. My terms for geek and nerd are the inverse of yours. To me, geeks are obsessed with things "normal" people aren't (like anime, video games, Lego, and speak Klingon) while the nerds are the ones who are going to be fixing everyone's computer and be your boss's boss's boss and do all the fancy mathematical work and whatnot.

Interesting...

-CF

A geek, nerd, or dork is someone who carefully defines and analyzes the words "geek," "nerd," and "dork," in order to "find" differences between them.

Geek: No social standing or skills, except with other geeks. Has an obsession with something, but it's not really an applicable skill like computer knowledge or school/mind. Geeks aren't intelligent, they just have obsessions, especially MMORPG's and video games. Typically not stylish.

Nerd: Usually don't have good social skills. Is smart, but not accepted, and not particularly styling. But better than geeks, because their obsessions are applicable.

Dork: A term of endearment synonymous with "weirdo". From the looks of these other posts, the use of "dork" as a term of endearment might be specific to my region/culture.

Note: having been a geek and now a nerd, I mean to harm to any that fall under my classifications.