The dictionary.com definition:

   hack·er1   Pronunciation Key  (h k r)
   n. Informal
    1. One who is proficient at using or programming a computer; a
       computer buff.
    2. One who uses programming skills to gain illegal access to a
       computer network or file.
    3. One who enthusiastically pursues a game or sport: a weekend tennis
       hacker.

Historically, the definitions of words in a language changes over time.  I'm
sure there is someone out there who is educated and can provide me with the
term for this phenomenon; and whoever you are, you can go fuck yourself.  I'm
not bragging to be a scholar, because that is something that I'm not.  However,
I am a hacker, and because of this I can make the following statements.

1) A hacker is someone who hacks.
2) Hacking is comprimising computers/computer networks.

A hacker is not someone who writes socalled "useful code" (operating systems,
applications, etc).  Hackers write tools to aide with the comprimise of computer
networks.  And hackers _use_ those tools; they do not sell them to the highest
bidder, and they do not use them to make a name for theirself so that they can
then become a "security consultant".

Silly rhetoric aside -- the important point is this: Hackers hack.

If you do not hack, you are not a hacker.  That simple.

On a semi-related note. . .

Anyone who claims to be an "ethical hacker" is a moron.  Hacking has nothing to
do with ethics.  There is no "ethical hacking" or "unethical hacking"; there is
only hacking.  If you have to dance around the definition of what a hacker is, 
or you have to dance around the definition of what hacking is, then what you do
is not hacking, and you are not a hacker.

-a PHC member